共用题干Earth Rocks onMost of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump against each other,slowly changing the shape of continents and oceans over millions and billions of years.Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly when this shift happened,however,is an open question.Now,an international group of researchers has an answer. They'ye found new evidence suggesting that Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than previous ones.Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in- sides.There,it melted before returning to the surface.In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old. The belt was once part of the seafloor,but now it is exposed to air.The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel cracks in the rock that have been filled in with a type of volcanic rock.To explain this structure,the scientists propose that tension in the crust caused the seafloor to crackopen long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the cracks.Finally,the whole area cooled,forming what we see today.That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once part of a plate under the ocean,beginning around 3.8 billion years ago.It took a long time for the melted crust to become hard.A:RightB:WrongC:Not mentioned
共用题干
Earth Rocks on
Most of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading
because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump
against each other,slowly changing the shape of continents and oceans over millions and billions of years.
Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at
first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly
when this shift happened,however,is an open question.
Now,an international group of researchers has an answer. They'ye found new evidence suggesting that
Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than
previous ones.
Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in
a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in-
sides.There,it melted before returning to the surface.
In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area
called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old.
The belt was once part of the seafloor,but now it is exposed to air.
The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel
cracks in the rock that have been filled in with a type of volcanic rock.
To explain this structure,the scientists propose that tension in the crust caused the seafloor to crack
open long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the
cracks.Finally,the whole area cooled,forming what we see today.
That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once
part of a plate under the ocean,beginning around 3.8 billion years ago.
Earth Rocks on
Most of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading
because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump
against each other,slowly changing the shape of continents and oceans over millions and billions of years.
Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at
first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly
when this shift happened,however,is an open question.
Now,an international group of researchers has an answer. They'ye found new evidence suggesting that
Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than
previous ones.
Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in
a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in-
sides.There,it melted before returning to the surface.
In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area
called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old.
The belt was once part of the seafloor,but now it is exposed to air.
The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel
cracks in the rock that have been filled in with a type of volcanic rock.
To explain this structure,the scientists propose that tension in the crust caused the seafloor to crack
open long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the
cracks.Finally,the whole area cooled,forming what we see today.
That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once
part of a plate under the ocean,beginning around 3.8 billion years ago.
It took a long time for the melted crust to become hard.
A:Right
B:Wrong
C:Not mentioned
A:Right
B:Wrong
C:Not mentioned
参考解析
解析：由第一段的前三句话可知，大部分时间我们认为地球是固定的这种想法是错误的。所 以该判断错误。
由第一段最后一句话可知，陆地和海洋是很多年前由于板块运动而形成的，所以此判 断正确。
由第一段最后一句话可知，并不是地球一冷却下来就形成了，地球是经过板块成千上 万亿年的运动慢慢形成的。
由第三段可知，地壳发生变化是在约38亿年前。所以此判断错误。
通读全文可知，文章中并没有提及溶化的地壳需要多久才能变硬。
由最后一段可知Isua的地壳带大约于38亿年前开始形成。
通读全文可知，文章并未提到Isua地壳带成了一个度假胜地。
由第一段最后一句话可知，陆地和海洋是很多年前由于板块运动而形成的，所以此判 断正确。
由第一段最后一句话可知，并不是地球一冷却下来就形成了，地球是经过板块成千上 万亿年的运动慢慢形成的。
由第三段可知，地壳发生变化是在约38亿年前。所以此判断错误。
通读全文可知，文章中并没有提及溶化的地壳需要多久才能变硬。
由最后一段可知Isua的地壳带大约于38亿年前开始形成。
通读全文可知，文章并未提到Isua地壳带成了一个度假胜地。
相关考题：
共用题干Eastern Quakes can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earth- quakes.The largest,a magnitude（量）5.6 quake,shook thousands of fans in a college football stadium, caused cracks in a few buildings and scared many people who had never felt a quake before.Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts of natural disasters.But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the US Geological Survey(USGS)estimate that several million earthquakes occur globally each year. That may sound scary,but people don't feel many of them because they happen in remote and unpopulated regions.Many quakes happen under the ocean,and others have a very small magnitude.Scientists know about small,remote quakes only because of very sensitive electronic devices called seis- mometers（地震仪）.These devices detect and measure the size of ground vibrations（震颤）produced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas.The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth ' s tectonic plates（构造板块）.Tectonic plates are huge pieces of Earth ' s crust（外壳）,sometimes many kilometers thick. Often, edges of these plates temporarily lock together. When plates push and scrape（擦）past each other earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble（轰轰作响）through portions of the landscape far from a plate ' s edges.Although less expected,these"mid-plate"small earthquakes can do substantial damage.Some of the biggest known examples hit the eastern half of the United States two centuries ago.Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.Few earthquakes happen without people'S awareness.A:RightB:WrongC:Not mentioned
共用题干A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The con-tinents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate,hot magma（岩浆）flows up to fill the space. New crust （地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long moun-tain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other. As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches. The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet. This is the lowest point on the ocean floor. If the leading edges of the two colli- ding plates carry continents , then the layers of rock in the overriding plate crumple（变皱）and fold .A plate that carried what is now India collided with the southern edge of the plate that carriedEurope and most of Asia. This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other. Severe earthquakes can occur. The SanAndreas Fault in California is a good example of this type of movement. This passage is mostly about______.A: effects of movements of the earth's platesB: different types of continentsC: the Marianas TrenchD: transform faults
共用题干Eastern Quakes can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earth- quakes.The largest,a magnitude（量）5.6 quake,shook thousands of fans in a college football stadium, caused cracks in a few buildings and scared many people who had never felt a quake before.Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts of natural disasters.But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the US Geological Survey(USGS)estimate that several million earthquakes occur globally each year. That may sound scary,but people don't feel many of them because they happen in remote and unpopulated regions.Many quakes happen under the ocean,and others have a very small magnitude.Scientists know about small,remote quakes only because of very sensitive electronic devices called seis- mometers（地震仪）.These devices detect and measure the size of ground vibrations（震颤）produced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas.The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth ' s tectonic plates（构造板块）.Tectonic plates are huge pieces of Earth ' s crust（外壳）,sometimes many kilometers thick. Often, edges of these plates temporarily lock together. When plates push and scrape（擦）past each other earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble（轰轰作响）through portions of the landscape far from a plate ' s edges.Although less expected,these"mid-plate"small earthquakes can do substantial damage.Some of the biggest known examples hit the eastern half of the United States two centuries ago.Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.The earthquake is the most unpredictable natural disaster.A:RightB:WrongC:Not mentioned
共用题干Eastern Quakes can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earth- quakes.The largest,a magnitude（量）5.6 quake,shook thousands of fans in a college football stadium, caused cracks in a few buildings and scared many people who had never felt a quake before.Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts of natural disasters.But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the US Geological Survey(USGS)estimate that several million earthquakes occur globally each year. That may sound scary,but people don't feel many of them because they happen in remote and unpopulated regions.Many quakes happen under the ocean,and others have a very small magnitude.Scientists know about small,remote quakes only because of very sensitive electronic devices called seis- mometers（地震仪）.These devices detect and measure the size of ground vibrations（震颤）produced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas.The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth ' s tectonic plates（构造板块）.Tectonic plates are huge pieces of Earth ' s crust（外壳）,sometimes many kilometers thick. Often, edges of these plates temporarily lock together. When plates push and scrape（擦）past each other earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble（轰轰作响）through portions of the landscape far from a plate ' s edges.Although less expected,these"mid-plate"small earthquakes can do substantial damage.Some of the biggest known examples hit the eastern half of the United States two centuries ago.Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.The earthquake that hit the eastern half of the United States two centuries ago is the biggest"mid-plate" one in history.A:RightB:WrongC:Not mentioned
共用题干A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The con-tinents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate,hot magma（岩浆）flows up to fill the space. New crust （地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long moun-tain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other. As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches. The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet. This is the lowest point on the ocean floor. If the leading edges of the two colli- ding plates carry continents , then the layers of rock in the overriding plate crumple（变皱）and fold .A plate that carried what is now India collided with the southern edge of the plate that carriedEurope and most of Asia. This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other. Severe earthquakes can occur. The SanAndreas Fault in California is a good example of this type of movement. To explain the effect of trenches,the writer gives the example of______.A: the sea floor in the Atlantic OceanB: the Himalayan MountainsC: EuropeD: India
共用题干A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The con-tinents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate,hot magma（岩浆）flows up to fill the space. New crust （地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long moun-tain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other. As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches. The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet. This is the lowest point on the ocean floor. If the leading edges of the two colli- ding plates carry continents , then the layers of rock in the overriding plate crumple（变皱）and fold .A plate that carried what is now India collided with the southern edge of the plate that carriedEurope and most of Asia. This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other. Severe earthquakes can occur. The SanAndreas Fault in California is a good example of this type of movement. The San Andreas Fault is an example of______.A: a severe earthquakeB: a California rock formationC: two plates moving apartD: two plates sliding past each other
共用题干Eastern Quakes can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earth- quakes.The largest,a magnitude（量）5.6 quake,shook thousands of fans in a college football stadium, caused cracks in a few buildings and scared many people who had never felt a quake before.Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts of natural disasters.But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the US Geological Survey(USGS)estimate that several million earthquakes occur globally each year. That may sound scary,but people don't feel many of them because they happen in remote and unpopulated regions.Many quakes happen under the ocean,and others have a very small magnitude.Scientists know about small,remote quakes only because of very sensitive electronic devices called seis- mometers（地震仪）.These devices detect and measure the size of ground vibrations（震颤）produced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas.The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth ' s tectonic plates（构造板块）.Tectonic plates are huge pieces of Earth ' s crust（外壳）,sometimes many kilometers thick. Often, edges of these plates temporarily lock together. When plates push and scrape（擦）past each other earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble（轰轰作响）through portions of the landscape far from a plate ' s edges.Although less expected,these"mid-plate"small earthquakes can do substantial damage.Some of the biggest known examples hit the eastern half of the United States two centuries ago.Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.Big earthquakes of a magnitude 8 or higher seldom happen far from the edges of tectonic plates.A:RightB:WrongC:Not mentioned
共用题干A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The con-tinents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate,hot magma（岩浆）flows up to fill the space. New crust （地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long moun-tain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other. As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches. The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet. This is the lowest point on the ocean floor. If the leading edges of the two colli- ding plates carry continents , then the layers of rock in the overriding plate crumple（变皱）and fold .A plate that carried what is now India collided with the southern edge of the plate that carriedEurope and most of Asia. This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other. Severe earthquakes can occur. The SanAndreas Fault in California is a good example of this type of movement. According to the passage,the earth is______.A: always changingB: becoming smallerC: moving fasterD: getting hotter
共用题干Earth Rocks onMost of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump against each other,slowly changing the shape of continents and oceans over millions and billions of years.Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly when this shift happened,however,is an open question.Now,an international group of researchers has an answer. They'ye found new evidence suggesting that Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than previous ones.Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in- sides.There,it melted before returning to the surface.In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old. The belt was once part of the seafloor,but now it is exposed to air.The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel cracks in the rock that have been filled in with a type of volcanic rock.To explain this structure,the scientists propose that tension in the crust caused the seafloor to crackopen long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the cracks.Finally,the whole area cooled,forming what we see today.That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once part of a plate under the ocean,beginning around 3.8 billion years ago.The formation of the Isua supracrustal belt is thought to have started about 3.8 billion years ago.A:RightB:WrongC:Not mentioned
共用题干Earth Rocks onMost of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump against each other,slowly changing the shape of continents and oceans over millions and billions of years.Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly when this shift happened,however,is an open question.Now,an international group of researchers has an answer. They'ye found new evidence suggesting that Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than previous ones.Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in- sides.There,it melted before returning to the surface.In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old. The belt was once part of the seafloor,but now it is exposed to air.The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel cracks in the rock that have been filled in with a type of volcanic rock.To explain this structure,the scientists propose that tension in the crust caused the seafloor to crackopen long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the cracks.Finally,the whole area cooled,forming what we see today.That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once part of a plate under the ocean,beginning around 3.8 billion years ago.The shape of lands and oceans are slowly changed with the movements of plates.A:RightB:WrongC:Not mentioned
共用题干第二篇A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The continents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate , hot magma（岩浆）flows up to fill the space. New crust（地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long mountain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other.As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches.The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet.This is the lowest point on the ocean floor. If the leading edges of the two colliding plates carry continents,then the layers of rock in the overriding plate crumple（变皱）and fold. A plate that carried what is now India collided with the southern edge of the plate that carried Europe and most of Asia.This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other.Severe earthquakes can occur. The San Andreas Fault in California is a good example of this type of movement.To explain the effect of trenches,the writer gives the example ofA:the sea floor in the Atlantic Ocean.B:the Himalayan Mountains.C:Europe.D:India.
共用题干第二篇A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The continents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate , hot magma（岩浆）flows up to fill the space. New crust（地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long mountain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other.As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches.The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet.This is the lowest point on the ocean floor. If the leading edges of the two colliding plates carry continents,then the layers of rock in the overriding plate crumple（变皱）and fold. A plate that carried what is now India collided with the southern edge of the plate that carried Europe and most of Asia.This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other.Severe earthquakes can occur. The San Andreas Fault in California is a good example of this type of movement.According to the passage,the earth isA:always changing.B:becoming smaller.C:moving faster.D:getting hotter.
共用题干Earth Rocks onMost of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump against each other,slowly changing the shape of continents and oceans over millions and billions of years.Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly when this shift happened,however,is an open question.Now,an international group of researchers has an answer. They'ye found new evidence suggesting that Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than previous ones.Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in- sides.There,it melted before returning to the surface.In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old. The belt was once part of the seafloor,but now it is exposed to air.The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel cracks in the rock that have been filled in with a type of volcanic rock.To explain this structure,the scientists propose that tension in the crust caused the seafloor to crackopen long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the cracks.Finally,the whole area cooled,forming what we see today.That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once part of a plate under the ocean,beginning around 3.8 billion years ago.Earth cooled down shortly after it was formed.A:RightB:WrongC:Not mentioned
共用题干Eastern Quakes Can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earthquakes. The largest,a magnitude 5 .6 quake,shook thousands of fans in a college football stadium,caused cracks in a few buildings and rattled the nerves of many people who had never felt a quake before. Oklahoma is not an area of the country famous for its quakes. If you watch the news on TV,you see reports about all sorts of natural disasters一 hurricanes,tornadoes,flooding and wildfires,to name a few. But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the U. S. Geological Survey estimate that several million earthquakes rattie the globe each year. That may sound scary,but people don't feel many of the tremors because they happen in remote and unpopulated regions.Many quakes happen under the ocean, and others have a very small magnitude,or shaking intensity.A magnitude 5.8 earthquake that struck central Virginia the afternoon of August 23, 2011,was felt from central Georgia to southeastern Canada. In many urban areas,including Washington,D.C.,and New York City(Wall Street shown),people crowded the streets while engineers inspected buildings.Scientists know about small,remote quakes only because of very sensitive electronic devices called seismometers.These devices detect and measure the size of ground vibrationsproduced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas. The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth's tectonic plates.Tectonic plates are huge pieces of Earth's crust,sometimes many kilometers thick. These plates cover our planet's surface like a jigsaw puzzle. Often,jagged edges of these plates temporarily lock together. When plates jostle and scrape past each other,earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble through portions of the landscape far from a plate's edges. Although less expected,these”mid-plate” tremors can do substantial damage. Some of the biggest known examples rattled the eastern half of the United States two centuries ago. Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.The earthquake that hit the eastern half of the United States two centuries ago is the biggest“mid-plate” one in history.A: RightB: WrongC: Not mentioned
共用题干第二篇A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The continents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate , hot magma（岩浆）flows up to fill the space. New crust（地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long mountain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other.As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches.The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet.This is the lowest point on the ocean floor. If the leading edges of the two colliding plates carry continents,then the layers of rock in the overriding plate crumple（变皱）and fold. A plate that carried what is now India collided with the southern edge of the plate that carried Europe and most of Asia.This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other.Severe earthquakes can occur. The San Andreas Fault in California is a good example of this type of movement.This passage is mostly aboutA:effects of movements of the earth's plates.B:different types of continents.C:the Marianas Trench.D:transform faults.
共用题干Earth Rocks onMost of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump against each other,slowly changing the shape of continents and oceans over millions and billions of years.Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly when this shift happened,however,is an open question.Now,an international group of researchers has an answer. They'ye found new evidence suggesting that Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than previous ones.Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in- sides.There,it melted before returning to the surface.In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old. The belt was once part of the seafloor,but now it is exposed to air.The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel cracks in the rock that have been filled in with a type of volcanic rock.To explain this structure,the scientists propose that tension in the crust caused the seafloor to crackopen long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the cracks.Finally,the whole area cooled,forming what we see today.That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once part of a plate under the ocean,beginning around 3.8 billion years ago.Scientists once estimated that Earth's crust started shifting three billion years ago.A:RightB:WrongC:Not mentioned
共用题干第二篇A Very Slow RideThe surface of the earth may seem very stable to you.But you might be amazed if you knew some of the things that are going on under that surface.The earth has an outer shell of rigid pieces called tectonic plates（地壳构造板块）.The plates include both ocean floor and dry land.Some have whole continents on top of them. The continents on top of the plates are just going along for a slow ride,moving only about four inches per year. But even this small movement causes three types of big interactions.One type is ocean ridges.These ridges develop in places where two plates are moving away from each other. As the plates separate , hot magma（岩浆）flows up to fill the space. New crust（地壳）builds up on the plate boundaries and causes ocean ridges. These ridges form long mountain ranges,which only rise above the ocean surface in a few places.Another type of reaction-trenches-occurs between two plates that are moving toward each other.As the plates meet,one bends downward and plunges underneath the other. This forms deep ocean trenches.The Marianas Trench off Guam in the western Pacific Ocean has a depth of more than 36,000 feet.This is the lowest point on the ocean floor. If the leading edges of the two colliding plates carry continents,then the layers of rock in the overriding plate crumple（变皱）and fold. A plate that carried what is now India collided with the southern edge of the plate that carried Europe and most of Asia.This caused the Himalayas,the world's highest mountains.The third reaction is transform faults（转换断层）.These faults occur where two plates that are traveling in opposite directions slide past each other.Severe earthquakes can occur. The San Andreas Fault in California is a good example of this type of movement.The San Andreas Fault is an example ofA:a severe earthquake.B:a California rock formation.C:two plates moving apart.D:two plates sliding past each other.
共用题干Eastern Quakes Can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earthquakes. The largest,a magnitude 5 .6 quake,shook thousands of fans in a college football stadium,caused cracks in a few buildings and rattled the nerves of many people who had never felt a quake before. Oklahoma is not an area of the country famous for its quakes. If you watch the news on TV,you see reports about all sorts of natural disasters一 hurricanes,tornadoes,flooding and wildfires,to name a few. But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the U. S. Geological Survey estimate that several million earthquakes rattie the globe each year. That may sound scary,but people don't feel many of the tremors because they happen in remote and unpopulated regions.Many quakes happen under the ocean, and others have a very small magnitude,or shaking intensity.A magnitude 5.8 earthquake that struck central Virginia the afternoon of August 23, 2011,was felt from central Georgia to southeastern Canada. In many urban areas,including Washington,D.C.,and New York City(Wall Street shown),people crowded the streets while engineers inspected buildings.Scientists know about small,remote quakes only because of very sensitive electronic devices called seismometers.These devices detect and measure the size of ground vibrationsproduced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas. The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth's tectonic plates.Tectonic plates are huge pieces of Earth's crust,sometimes many kilometers thick. These plates cover our planet's surface like a jigsaw puzzle. Often,jagged edges of these plates temporarily lock together. When plates jostle and scrape past each other,earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble through portions of the landscape far from a plate's edges. Although less expected,these”mid-plate” tremors can do substantial damage. Some of the biggest known examples rattled the eastern half of the United States two centuries ago. Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.Few earthquakes happen without people's awareness.A: RightB: WrongC: Not mentioned
共用题干Eastern Quakes Can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earthquakes. The largest,a magnitude 5 .6 quake,shook thousands of fans in a college football stadium,caused cracks in a few buildings and rattled the nerves of many people who had never felt a quake before. Oklahoma is not an area of the country famous for its quakes. If you watch the news on TV,you see reports about all sorts of natural disasters一 hurricanes,tornadoes,flooding and wildfires,to name a few. But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the U. S. Geological Survey estimate that several million earthquakes rattie the globe each year. That may sound scary,but people don't feel many of the tremors because they happen in remote and unpopulated regions.Many quakes happen under the ocean, and others have a very small magnitude,or shaking intensity.A magnitude 5.8 earthquake that struck central Virginia the afternoon of August 23, 2011,was felt from central Georgia to southeastern Canada. In many urban areas,including Washington,D.C.,and New York City(Wall Street shown),people crowded the streets while engineers inspected buildings.Scientists know about small,remote quakes only because of very sensitive electronic devices called seismometers.These devices detect and measure the size of ground vibrationsproduced by earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes each year.Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas. The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big ones typically occur along the edges of Earth's tectonic plates.Tectonic plates are huge pieces of Earth's crust,sometimes many kilometers thick. These plates cover our planet's surface like a jigsaw puzzle. Often,jagged edges of these plates temporarily lock together. When plates jostle and scrape past each other,earthquakes occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.But sometimes earthquakes rumble through portions of the landscape far from a plate's edges. Although less expected,these”mid-plate” tremors can do substantial damage. Some of the biggest known examples rattled the eastern half of the United States two centuries ago. Today,scientists are still puzzling over why the quakes occurred and when similar ones might occur.Big earthquakes of a magnitude 8 or higher seldom happen far from the edges of tectonic plates.A: RightB: WrongC: Not mentioned
共用题干Earth Rocks onMost of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump against each other,slowly changing the shape of continents and oceans over millions and billions of years.Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly when this shift happened,however,is an open question.Now,an international group of researchers has an answer. They'ye found new evidence suggesting that Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than previous ones.Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in- sides.There,it melted before returning to the surface.In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old. The belt was once part of the seafloor,but now it is exposed to air.The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel cracks in the rock that have been filled in with a type of volcanic rock.To explain this structure,the scientists propose that tension in the crust caused the seafloor to crackopen long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the cracks.Finally,the whole area cooled,forming what we see today.That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once part of a plate under the ocean,beginning around 3.8 billion years ago.The ground beneath our feet is indeed still.A:RightB:WrongC:Not mentioned
共用题干A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. Alan says that ordinary people who live in the town will probably soon______.A: be able to buy new housesB: choose to live near the stationC: open new shops and hotelsD: have less money
共用题干A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. What will cause traffic jams?A: Buildings on Parson's Place.B: Building near the railway station.C: Travelers in the narrow streets.D: People going to the shops and hotels.
共用题干A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. Which of these posters has Alan made?A: SAVE OUR SPORTh GROUNDB: SAY NO TO HOUSES ON PARSON'S PLACEC: WE NEED HOMES NOT HOTELSD: USE THE TRAIN NOT THE ROAD
共用题干A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. Why has Alan written this letter?A: To persuade the government to build new houses.B: To protest about a new motorway near the town.C: To encourage more people in the town to use Parson's Place.D: To inform other people about the builders' plans.
共用题干A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. In Alan's opinion,why is Parson's Place particularly important?A: Because there's a football ground nearby.B: Because lots of people live near it.C: Because it is a place near the town where people can enjoy nature.D: Because local people can get there easily by car from the town.
共用题干Eastern Quakes can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earthquakes.The largest,a magnitude 5.6 quake,shook thousands of fans in a college football itadium, caused cracks in a few buildings and rattled the nerves of many people who had never felt a quake before. Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts of natural disasters一hurricanes,tornadoes,flooding and wildfires,to name a few.But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the U.S.Geological Survey estimate that several million earthquakes rattle the globe eachyear. That mnay sound scary,but people don'I feel many of the tremors because they happen in remote and unpopulated regions.Many quakes happen under the ocean,and othlers have a very small magnitude,or shaking intensity..A magnitude 5.8 earthquake that struck central Virginia the afternoon of August 23,2011,was felt from central Georgia to southeastern Canada.In iilany urbanl areas,including Washington,D.C.,dnd New York City(Wall Street shown),people crowded the streets while engineer inspected buildings.Credit: Wikimnedia/Alex Tahak.Scientists know about small,remote quakes only because of very sensitive electronic devices called seis- mometers.These devices detect and measure the size of ground vibrations produced by earthquakes. Altogether,USGS researchers use seismornetero to identify and locate about 20,000 earthquakseach year.Although earthquakes can happen anywhere in the world,really big quakeg occur only in。erttiin areas.The largest ones register a magnitude S or higher and happen, on average,only once each year. Such big ones typically occur along the edges of Earth’s tectonic plates.Tectonic plates are huge pieces of Earth’s crust,sornetinies many kilometers thick.These plates cover our planet'ssurface ike a jigsaw puzzle.Often,jagged edges of these plates temporarily lock together. When riates jostle and serape past each other earthquakes occur. On。、crage,tectonic plates move very slowly一 about the same speed as sour fingernails grow.But sometimes earthquakes rumble through portions of the landscape far from a plate'S edges.Although less cxpcctcd,these"mid-plate"tremors can do substontaI damage,Some of the biggest known examples rattled the eastern haif of the United States two centuries ago.Today,scientists are still puzzling over why the quakes occurred and when similar ones nught occur.Few earthquakes happen without people’s awareness.A:RightB:WrongC:Not mentioned
共用题干Eastern Quakes can Trigger Big ShakesIn the first week of November 2011,people in central Oklahoma experienced more than two dozen earthquakes.The largest,a magnitude 5.6 quake,shook thousands of fans in a college football itadium, caused cracks in a few buildings and rattled the nerves of many people who had never felt a quake before. Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts of natural disasters一hurricanes,tornadoes,flooding and wildfires,to name a few.But the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.Researchers at the U.S.Geological Survey estimate that several million earthquakes rattle the globe eachyear. That mnay sound scary,but people don'I feel many of the tremors because they happen in remote and unpopulated regions.Many quakes happen under the ocean,and othlers have a very small magnitude,or shaking intensity..A magnitude 5.8 earthquake that struck central Virginia the afternoon of August 23,2011,was felt from central Georgia to southeastern Canada.In iilany urbanl areas,including Washington,D.C.,dnd New York City(Wall Street shown),people crowded the streets while engineer inspected buildings.Credit: Wikimnedia/Alex Tahak.Scientists know about small,remote quakes only because of very sensitive electronic devices called seis- mometers.These devices detect and measure the size of ground vibrations produced by earthquakes. Altogether,USGS researchers use seismornetero to identify and locate about 20,000 earthquakseach year.Although earthquakes can happen anywhere in the world,really big quakeg occur only in。erttiin areas.The largest ones register a magnitude S or higher and happen, on average,only once each year. Such big ones typically occur along the edges of Earth’s tectonic plates.Tectonic plates are huge pieces of Earth’s crust,sornetinies many kilometers thick.These plates cover our planet'ssurface ike a jigsaw puzzle.Often,jagged edges of these plates temporarily lock together. When riates jostle and serape past each other earthquakes occur. On。、crage,tectonic plates move very slowly一 about the same speed as sour fingernails grow.But sometimes earthquakes rumble through portions of the landscape far from a plate'S edges.Although less cxpcctcd,these"mid-plate"tremors can do substontaI damage,Some of the biggest known examples rattled the eastern haif of the United States two centuries ago.Today,scientists are still puzzling over why the quakes occurred and when similar ones nught occur.Big earthquakes of a magnitude 8 or higher seldom happen far from the edges of tectonic plates.A:RightB:WrongC: Not mentioned