单选题（）means the curve on the earth’s surface which cuts all the meridians at the same angle.AGreat CircleBPosition LineCRhumb lineDTrue Bearing
单选题
（）means the curve on the earth’s surface which cuts all the meridians at the same angle.
A
Great Circle
B
Position Line
C
Rhumb line
D
True Bearing
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It can be learned from the passage that about four billion years ago ______.A. the earth was in molten stateB. the earth surface temperature was above 100℃C. the earth surface temperature was below 100℃D. rain water could remain on the earth
A greenhouse is a building made of glass which is used for keeping plants when the outside temperature is low. In a similar way there are several gases in the atmosphere which trap(捕捉)the heat produced by the sun and prevent it from escaping. These gases are known as"greenhouse gases"，and the way in which they trap heat in the atmosphere is called the "greenhouse effect". This is not simply air pollution. Most of the main greenhouse gases exist naturally in small amounts in our atmosphere, and without them earth would be 30 degrees colder and human life would not exist. In other words, the greenhouse effect is a natural course which is to some degree helpful to us.The problem is that in the last century and a half, we have been putting too many of these gases into the earth's atmosphere by burning large quantities of coal and oil and by cutting down forests. The rapid increase in greenhouse gases is making the world warmer. The world's temperature has already gone up by half a degree this century, and the sea level has risen by 10 centimetres. If the amount of carbon dioxide(二氧化碳)in the atmosphere doubles, there will probably be a rise in the earth's temperature of between 1 and 4 degrees. This may seem a small increase, but it would be enough to cause major changes in geography and agriculture. Large areas of the world would be flooded, and some areas would become dry and unable to produce crops. It is important, too, to consider that there may be a delay of about 30 years in the greenhouse effect. This means that we are probably experiencing only now the effect of the gases put into the atmosphere before the 1960s. Since then, our use of these gases has greatly increased.1. The"greenhouse effect"means _____.A. the way in which gases are used for keeping plants warmB. a natural course which is some degree helpful to usC. the way"greenhouse gases"trap heat on the earthD. the whole course in which greenhouse gases prevent heat2. If there were no greenhouse effect, _____.A. no plants would grow on our planetB. earth would be thirty degrees colderC. man could not live on the earthD. All of the above answers are correct3. Which of the following is NOT true? _____A. Burning too much coal and oil produces lots of greenhouse gases.B. It has become warmer on the earth now than in the past.C. Gases put into the atmosphere now will affect the earth years later.D. The temperature in a greenhouse is as high as that in the atmosphere.4. Suppose the earth's temperature rose by 3 degrees, _____.A. great harm would be done to mankindB. the sea level would go by 10 centimetresC. all the land in the world would be floodedD. crops would be unable to grow on the earth5. This passage mainly deals with _____.A. the concept(概念)and harm of greenhouse effectB. the relation between greenhouse gases and manC. the concept and change of greenhouse effectD. the effect of the rise of the earth's temperature
____ is covered with heavy snow. A.The earth's surfaceB.The surface of earthC.The surface earthD.The earth surface
According to the text. which of the following is NOT true?A. Soil forms from weathered rock on the earth surface.B. The deeper layer of soil is darker in colour than the surface soil.C. Air pollution is partially responsible for acid soil.D. Groundwater tends to carry away nutrients for plant growth.
Which factor(s) might indicate that a towline should be removed from service?A.Visible damage to the towline，including fishhooksB.Measurements showing a decrease in diameterC.A surface condition of corrosion and discolorationD.All of the above
Which statement about the gyrocompass is FALSE ________．A.Its accuracy remains the same at all latitudesB.It seeks the true meridianC.It can be used near the Earth's magnetic polesD.If an error exists，it is the same on all headings
______means the curve on the earth’s surface which cuts all the meridians at the same angle.A.Great CircleB.Position LineC.Rhumb LineD.True Bearing
共用题干第三篇“Life Form Found" on Saturn ' s TitanScientists say they have discovered hints of alien life on the Saturn'5 moon.The discovery of a sort of life was announced after researchers at the US space agency,NASA,analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn's biggest moon.Scientists have reportedly discovered clues showing primitive alien beings are"breathing"in Titan's dense atmosphere filled with hydrogen.They argue that hydrogen gets absorbed before hitting Titan's planet-like surface covered with methane lakes and rivers.This,they say,points to the existence of some"bugs"consuming the hydrogen at the surface of the moon less than half the size of the Earth."We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan,similar to the way we consume oxygen on Earth,"says NASA scientist Chris McKay."If these signs do turn out to be a sign of life,it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."To date,scientists have not yet detected this form of life anywhere,though there are liquid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan,wheretemperatures are around minus 17 Kelvin(minus 290 degrees Farenheit),a methane-based organism would have to use a substance that is liquid as its medium for living processes,but not water itself. Water is frozen solid on Titan'5 surface and much too cold to support life as we know it.Scientists had expected the Sun'5 interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan'5 surface.But Cassini detected no acetylene on the surface.The absence of detectable acetylene on the Titan's surface can very well have a non-biological explana-tion,said Mark Allen,a principal investigator of the NASA Titan team."Scientific conservatism suggests that a biological explanation should be the last choice after all non- biological explanations are addressed,"Allen said."We have a lot of work to do to rule out possible non-bio- logical explanations.It is more likely that a chemical process,without biology,can explain these results."Which of the following statements about Titan is true?A:It is as large as the Earth.B:There is acetylene on its surface.C:Water on it acts as a life supporting medium.D:Hydrogen consumption is reported to be on it.
共用题干Weight on and off the Earth We are so used to.our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted.Because we can feel that things are heavy,we think of "weight"as being a fixed quality in an object,but it is not really fixed at all.If you could take a one-pound packet of butter 4,000 miles out from the earth,it would weigh only a quarter of a pound. Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space?The reason is this:all objects have a natural attraction for all other objects;this is called gravitational attraction.But this power of attraction between two obects gets weaker as they get farther apart.When the butter was at the surface of the earth,it was 4,000 miles from the center.When we took the butter 4,000 miles out,it was 8,000 miles from the center,which is twice the distance.If you double the distance between two objects,their gravitational attraction decreases two times two.If you treble the distance, it gets nine times weaker(three times three)and so on. So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth. What about the weight of our pound of butter on the surface of the moon?At the distance the puii of the earth is about 4,000 times smaller than it is here on the surface,so we can forget all about the earth-pull on our butter. On the other hand,on the moon there will be an attraction between the butter and the moon,but the butter will weigh only about one-sixth as much as it does on the earth.This is because the moon is so much smaller than the earth.The amount of gravitational pull that a body produces depends on the amount of material in it.A packet of butter has a gravitational pull of its own;but this is very small in relation to the pull of something as large as the moon,or the earth,or the sun.According to the passage,"weight"should be understood in the sense thatA:it is fixed if it is outside the earth's gravitational puliB:it decreases four times when it is 4,000 miles from the earth's centerC:it varies with the change of the gravitational attraction between two objectsD:things increase in amount as they are closer to the earth's surface
共用题干Weight on and off the Earth We are so used to.our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted.Because we can feel that things are heavy,we think of "weight"as being a fixed quality in an object,but it is not really fixed at all.If you could take a one-pound packet of butter 4,000 miles out from the earth,it would weigh only a quarter of a pound. Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space?The reason is this:all objects have a natural attraction for all other objects;this is called gravitational attraction.But this power of attraction between two obects gets weaker as they get farther apart.When the butter was at the surface of the earth,it was 4,000 miles from the center.When we took the butter 4,000 miles out,it was 8,000 miles from the center,which is twice the distance.If you double the distance between two objects,their gravitational attraction decreases two times two.If you treble the distance, it gets nine times weaker(three times three)and so on. So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth. What about the weight of our pound of butter on the surface of the moon?At the distance the puii of the earth is about 4,000 times smaller than it is here on the surface,so we can forget all about the earth-pull on our butter. On the other hand,on the moon there will be an attraction between the butter and the moon,but the butter will weigh only about one-sixth as much as it does on the earth.This is because the moon is so much smaller than the earth.The amount of gravitational pull that a body produces depends on the amount of material in it.A packet of butter has a gravitational pull of its own;but this is very small in relation to the pull of something as large as the moon,or the earth,or the sun.How much would four pounds of tea weigh if it was taken 4,000 miles out from the surface of the earth?A:1 pound. B:2 pounds. C:3 pounds. D:4 pounds.
共用题干Weight on and off the Earth We are so used to.our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted.Because we can feel that things are heavy,we think of "weight"as being a fixed quality in an object,but it is not really fixed at all.If you could take a one-pound packet of butter 4,000 miles out from the earth,it would weigh only a quarter of a pound. Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space?The reason is this:all objects have a natural attraction for all other objects;this is called gravitational attraction.But this power of attraction between two obects gets weaker as they get farther apart.When the butter was at the surface of the earth,it was 4,000 miles from the center.When we took the butter 4,000 miles out,it was 8,000 miles from the center,which is twice the distance.If you double the distance between two objects,their gravitational attraction decreases two times two.If you treble the distance, it gets nine times weaker(three times three)and so on. So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth. What about the weight of our pound of butter on the surface of the moon?At the distance the puii of the earth is about 4,000 times smaller than it is here on the surface,so we can forget all about the earth-pull on our butter. On the other hand,on the moon there will be an attraction between the butter and the moon,but the butter will weigh only about one-sixth as much as it does on the earth.This is because the moon is so much smaller than the earth.The amount of gravitational pull that a body produces depends on the amount of material in it.A packet of butter has a gravitational pull of its own;but this is very small in relation to the pull of something as large as the moon,or the earth,or the sun.We do not feel the gravitational pull of a packet of butter becauseA:it is too small to have a gravitational pull of its ownB:its puil is so small that we tend to ignore itC:its pui1 disappears in the presence of the earth's gravitationD:it tends to melt and loses its gravitational puli
共用题干Where Did the Earth's Water Come From?Earth is located within the"snow line"of the solar system,the region closest to the Sun where H2 0 is primarily in liquid or gaseous form,if at all.______(46)The snow line phenomena is reflected in the water content of planets like Mercury,Venus,and Mars. Water is absent on Mercury.On Venus,H2O only exists as a trace element in the atmosphere.Mars only has a thin veneer of ice in its polar regions.In general,water is rare within the snow line.Why does Earth have so much water relative to the other inner planets?71%of the surface is covered in the oceans,more than half of which is deeper than 3,000 meters,with an approximate total volume of 1.3 billion cu km.______(47)There are various theories as to where all the Earth's water came from,but several theories have fared better than the others.______(48)When the Earth was in the process of forming,with a radius just 40%smaller than at present,it would have had enough gravity to hold on to a tenuous atmosphere with water vapor. The first water vapor on the planet would have come from the planet's internals,where volatile(low weight)chemicals would have a tendency to float to the top,and heavy chemicals(iron and nickel)would sink.Though the first of Earth's water came about through volcanism,this alone probably didn't produce enough to form stable pools on the surface.______(49)Comparing the isotope ratios of water on Earth and water from comets and asteroids has revealed that the majority of the Earth's water comes from asteroids.Throughout its history,Earth's water has increased in volume due to biological processes. In the early seas of Earth,hydrogen sulfide would have been in great supply,which,when reacted with carbon dioxide from the atmosphere during photosynthesis in sulfide-reducing bacteria,would have produced hydrogen,sulfur,and water.______(50)________（49）A: More water was added to the planet during several hypothesized large impacts from asteroids from the outer asteroid belt.B:We know that the oceans existed as early as 100 million years after the formation of the Earth.C:Still,the oceans only make up 0.023%of the Earth's total mass.D:Astronomers say Earth s water may have come from space.E:The snow line is located in the outerasteroid belt,between the orbits of Mars and Jupiter. F: Many geologists believe that the majority of Earth's water generated through this process.
共用题干Weight on and off the Earth We are so used to.our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted.Because we can feel that things are heavy,we think of "weight"as being a fixed quality in an object,but it is not really fixed at all.If you could take a one-pound packet of butter 4,000 miles out from the earth,it would weigh only a quarter of a pound. Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space?The reason is this:all objects have a natural attraction for all other objects;this is called gravitational attraction.But this power of attraction between two obects gets weaker as they get farther apart.When the butter was at the surface of the earth,it was 4,000 miles from the center.When we took the butter 4,000 miles out,it was 8,000 miles from the center,which is twice the distance.If you double the distance between two objects,their gravitational attraction decreases two times two.If you treble the distance, it gets nine times weaker(three times three)and so on. So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth. What about the weight of our pound of butter on the surface of the moon?At the distance the puii of the earth is about 4,000 times smaller than it is here on the surface,so we can forget all about the earth-pull on our butter. On the other hand,on the moon there will be an attraction between the butter and the moon,but the butter will weigh only about one-sixth as much as it does on the earth.This is because the moon is so much smaller than the earth.The amount of gravitational pull that a body produces depends on the amount of material in it.A packet of butter has a gravitational pull of its own;but this is very small in relation to the pull of something as large as the moon,or the earth,or the sun.We find it hard to break free from ideas connected with living on the earth because______.A:it demands too great an effort for us to do soB:we are too familiar with the way things are to question the ideasC:we have proved that those ideas are correctD:we are so sure of ourselves that we never doubt anything on the earth
共用题干Weight on and off the Earth We are so used to.our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted.Because we can feel that things are heavy,we think of "weight"as being a fixed quality in an object,but it is not really fixed at all.If you could take a one-pound packet of butter 4,000 miles out from the earth,it would weigh only a quarter of a pound. Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space?The reason is this:all objects have a natural attraction for all other objects;this is called gravitational attraction.But this power of attraction between two obects gets weaker as they get farther apart.When the butter was at the surface of the earth,it was 4,000 miles from the center.When we took the butter 4,000 miles out,it was 8,000 miles from the center,which is twice the distance.If you double the distance between two objects,their gravitational attraction decreases two times two.If you treble the distance, it gets nine times weaker(three times three)and so on. So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth. What about the weight of our pound of butter on the surface of the moon?At the distance the puii of the earth is about 4,000 times smaller than it is here on the surface,so we can forget all about the earth-pull on our butter. On the other hand,on the moon there will be an attraction between the butter and the moon,but the butter will weigh only about one-sixth as much as it does on the earth.This is because the moon is so much smaller than the earth.The amount of gravitational pull that a body produces depends on the amount of material in it.A packet of butter has a gravitational pull of its own;but this is very small in relation to the pull of something as large as the moon,or the earth,or the sun.The main idea of this passage isA:different weight systems in different placesB:freedom from traditional ideasC:traveling from the earth to the moonD:the effect of gravitation on weight
The power saving state in which a computer cuts power to all its unneeded parts and copies the RAM content to the hard drive is called（）A、hibernateB、shutdownC、sleepD、hypervisor
单选题Which statement about the gyrocompass is FALSE（）.AIts accuracy remains the same at all latitudesBIt seeks the true meridianCIt can be used near the Earth's magnetic polesDIf an error exists，it is the same on all headings
单选题A plane that cuts the Earth’s surface and passes through the poles will always form（）.Athe equatorBa loxodromic curveCa small circleDa meridian
单选题A plane perpendicular to the polar axis will never form what line on the Earth’s surface? （）AGreat circleBEquatorCSmall circleDMeridian
单选题The equator is（）.Athe primary great circle of the Earth perpendicular to the axisBthe line to which all celestial observations are reducedCthe line from which a celestial body's altitude is measuredDAll of the above
单选题According to the passage, atmospheric carbon dioxide performs all of the following functions EXCEPT: _____.Aabsorbing radiation at visible wavelengthsBabsorbing infrared radiationCabsorbing outgoing radiation from the EarthDhelping to retain heat near the Earth’s surface
单选题The direction of the surface wind is（）.Adirectly from high pressure toward low pressureBdirectly from low pressure toward high pressureCfrom high pressure toward low pressure deflected by the earth's rotationDfrom low pressure toward high pressure deflected by the earth's rotation
单选题Only a small part of the sun’s energy reaches the earth’ s surface because most of it is ______.Aabsorbed by the clouds in the lower atmosphereBreflected by the gases in the upper atmosphereClost in the upper and lower atmosphereDused to evaporate water from the oceans and lakes
单选题Without the sun’s light _____ the earth’s surface, it would be so cold that life could not exist on the earth.AwarmsBwarmedCwarmingDto warm
单选题What is the basic principle of the magnetic compass（）.AMagnetic materials of the same polarity repel each other and those of opposite polarity attractBThe Earth's magnetic lines of force are parallel to the surface of the EarthCMagnetic meridians connect points of equal magnetic variationDThe compass needle（s）will，when properly compensated，lie parallel to the isogonic lines of the Earth
单选题_____ most of the earth's surface is covered by water, fresh water is very rare and precious.AAsBOnceCIfDAlthough
单选题A plane that cuts the Earth’s surface at any angle and passes through the center will always form（）.Athe equatorBa great circleCa small circleDa meridian
单选题The points on the earth’s surface where the magnetic dip is 90° are（）.AAlong the magnetic equatorBConnected by the isoclinal lineCThe isoporsDThe magnetic poles