共用题干第一篇Putting Plants to WorkUsing the power of the sun is nothing new.People have had solar-powered calculators and buildings withsolar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as anenergy source for billions of years.Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化 碳）,and water into sugarsand starche（淀粉）,stored energy that the piants can use. This conversion process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly how plants do it.Some scientists are trying to get plants,or biological cells that act like plants, to work as very small photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient- ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe- sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of the time.Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐） from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air is present.Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work,they may be able to speed the cells' activity and produce larger quantities of hydrogen.The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms." Algae are able to use solar energy to produce hydrogen when_______________.A:they are grown in narrow-necked bottlesB:there is no oxygen in the airC:there is enough oxygen in the airD:enough starch is stored
共用题干
第一篇
Putting Plants to Work
Using the power of the sun is nothing new.People have had solar-powered calculators and buildings with
solar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as an
energy source for billions of years.
Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化
碳）,and water into sugars
and starche（淀粉）,stored energy that the piants can use. This conversion
process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and
expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly
how plants do it.
Some scientists are trying to get plants,or biological cells that act like plants, to work as very small
photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in
Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen
instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient-
ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.
The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe-
sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the
sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-
drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of
the time.
Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap
energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐）
from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air
is present.
Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much
hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently
from algae. With more work,they may be able to speed the cells' activity and produce larger quantities
of hydrogen.
The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to
get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a
pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms."
第一篇
Putting Plants to Work
Using the power of the sun is nothing new.People have had solar-powered calculators and buildings with
solar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as an
energy source for billions of years.
Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化
碳）,and water into sugars
and starche（淀粉）,stored energy that the piants can use. This conversion
process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and
expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly
how plants do it.
Some scientists are trying to get plants,or biological cells that act like plants, to work as very small
photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in
Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen
instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient-
ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.
The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe-
sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the
sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-
drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of
the time.
Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap
energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐）
from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air
is present.
Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much
hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently
from algae. With more work,they may be able to speed the cells' activity and produce larger quantities
of hydrogen.
The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to
get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a
pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms."
Algae are able to use solar energy to produce hydrogen when_______________.
A:they are grown in narrow-necked bottles
B:there is no oxygen in the air
C:there is enough oxygen in the air
D:enough starch is stored
A:they are grown in narrow-necked bottles
B:there is no oxygen in the air
C:there is enough oxygen in the air
D:enough starch is stored
参考解析
解析：由第一段第三、四句话“But plants are the real experts.They' ye been using sunlight as an energy source for billions of years.”可知答案。
文章的第三段说，科学家企图将植物或植物类生物细胞作为微型光合作用能源供应站 来研究，并举例说，他们正在用绿藻进行实验，若成功，绿藻所产生的氢气将可用来为汽车的燃 料电池充电。所以答案是D。
由文章第四段最后两句“…algae will produce hydrogen in an airfree environment.It' s the oxygen in the air that prevents algae from making hydrogen most of the time.（……绿藻在没有空气 的环境下能产生氢气，是空气中的氧气在阻止绿藻制造氢气。）”可知选B。
A、B都不是正确答案，因为短文的第五段、第六段告诉我们，remove the sulfate和work in an airfree environment都是可能的，但问题是两者都有弊端，使氢气的制造不那么容易。C所 述内容就是困难之一：绿藻细胞因为没有了sulfate而减缓工作速度，因此产生不了多少氢气。 D项与第四段末尾所说的“是空气中的氧气在阻止绿藻制造氢气”矛盾。故选C。
根据最后一段Ghirardi所说的话可知，绿藻可以在任何地方生长，而且用途广泛，联系 此段首句可知Ghirardi所说的意在表示绿藻易于广泛应用，有望成为一种好的能源。故选A。 B项未提到，C项“它们将被到处种植”也不是Ghirardi的话的真正意思，他只是说绿藻易于广 泛种植。D项是对文中“feed”一词所在句的错误理解，feed在此意为“养”。第二篇 文章主要讲的是公共土地在美国能源生产方面的重大作用，分别从产量、税收、未开发的传 统能源、替代能源占全国的份额以及能源开发需求等方面进行了介绍。
文章的第三段说，科学家企图将植物或植物类生物细胞作为微型光合作用能源供应站 来研究，并举例说，他们正在用绿藻进行实验，若成功，绿藻所产生的氢气将可用来为汽车的燃 料电池充电。所以答案是D。
由文章第四段最后两句“…algae will produce hydrogen in an airfree environment.It' s the oxygen in the air that prevents algae from making hydrogen most of the time.（……绿藻在没有空气 的环境下能产生氢气，是空气中的氧气在阻止绿藻制造氢气。）”可知选B。
A、B都不是正确答案，因为短文的第五段、第六段告诉我们，remove the sulfate和work in an airfree environment都是可能的，但问题是两者都有弊端，使氢气的制造不那么容易。C所 述内容就是困难之一：绿藻细胞因为没有了sulfate而减缓工作速度，因此产生不了多少氢气。 D项与第四段末尾所说的“是空气中的氧气在阻止绿藻制造氢气”矛盾。故选C。
根据最后一段Ghirardi所说的话可知，绿藻可以在任何地方生长，而且用途广泛，联系 此段首句可知Ghirardi所说的意在表示绿藻易于广泛应用，有望成为一种好的能源。故选A。 B项未提到，C项“它们将被到处种植”也不是Ghirardi的话的真正意思，他只是说绿藻易于广 泛种植。D项是对文中“feed”一词所在句的错误理解，feed在此意为“养”。第二篇 文章主要讲的是公共土地在美国能源生产方面的重大作用，分别从产量、税收、未开发的传 统能源、替代能源占全国的份额以及能源开发需求等方面进行了介绍。
相关考题：
The two plants he had ever worked for have _______ due to foreign competition. (A) shut down(B) shut up(C) shut off(D) shut away
CPlants can’t communicate by moving or making sounds, as most animals do. Instead, plants produce volatile compounds, chemicals that easily change from a liquid to a gas. A flower’s sweet smell, for example, comes from volatile compounds that the plant produces to attract insects such as bugs and bees.Plants can also detect volatile compounds produced by other plants. A tree under attack by hungry insects, for instance, may give off volatile compounds that let other trees know about the attack, In response, the other trees may send off chemicals to keep the bugs away- or even chemicals that attract the bugs’ natural enemies.Now scientists have created a quick way to understand what plants are saying: a chemical sensor(传感器) called an electronic nose. The “e-nose” can tell compounds that crop plants make when they’re attacked. Scientists say the e-nose could help quickly detest whether plants are being eaten by insects. But today the only way to detect such insects is to visually inspect individual plants. This is a challenging task for managers of greenhouses, enclosed gardens that can house thousands of plants.The research team worked with an e-nose that recognizes volatile compounds. Inside the device, 13 sensors chemically react with volatile compounds. Based on these interactions, the e-nose gives off electronic signals that the scientists analyze using computer software.To test the nose, the team presented it with healthy leaves from cucumber, pepper and tomato plants, all common greenhouse crops. Then the scientists collected samples of air around damaged leaves from each type of crop. These plants had been damaged by insects, or by scientists who made holes in the leaves with a hole punch (打孔器).The e-nose, it turns out, could identify healthy cucumber, pepper and tomato plants based on the volatile compounds they produce. It could also identify tomato leaves that had been damaged. But even more impressive, the device could tell which type of damage – by insects or with a hole punch – had been done to the tomato leaves.With some fine tuning, a device like the e-nose could one day be used in greenhouses to quickly spot harmful bugs, the researchers say. A device like this could also be used to identify fruits that are perfectly ripe and ready to pick and eat, says Natalia Dudareve, a biochemist at Purdue University in West Lafayette, Ind. who studies smells of flowers and plants. Hopefully, scientists believe, the device could bring large benefits to greenhouse managers in the near future.49. We learn from the text that plants communicate with each other by______.A. making some sounds B. waving their leavesC. producing some chemicals D. sending out electronic signals
AWhy do plants grow in some places and not in others? Why does some land have so much growing on it，while other land has almost no plants growing on it at all?To grow plants need several things． One is warmth． In very cold places almost nothing grows． Plants also need water． In very dry parts of the earth only a few unusual plants can grow． That's why dry deserts everywhere are almost not covered by trees or grass．Plants must also have a place in which to f，ut down their roots and grow． They find it diffi-culr to grow on hard land． The town is built on hard land． The plants here have only the soil found between the cracks of the stones Io grow in．Another thing plants must have before they can grow is food．Whar will happen if we try to make things grow on the sandy beach? A few plants，such as beach grass，will grow in sand，L ut most plants won-t． Even if the weather is warm enough．and we water the plants each day． Many of them will die because the sand on this beach has al-most no food for plants．( )21． According to the passage，plants need _________ things to grow well．A． twoB． threeC． fourD． five
共用题干第一篇Putting Plants to WorkUsing the power of the sun is nothing new.People have had solar-powered calculators and buildings withsolar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as anenergy source for billions of years.Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化 碳）,and water into sugarsand starche（淀粉）,stored energy that the piants can use. This conversion process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly how plants do it.Some scientists are trying to get plants,or biological cells that act like plants, to work as very small photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient- ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe- sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of the time.Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐） from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air is present.Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work,they may be able to speed the cells' activity and produce larger quantities of hydrogen.The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms." Researchers find it difficult to make algae produce hydrogen efficiently because_______________.A:it is hard to create an airfree environmentB:it is expensive to remove the sulfate from the environmentC:removing the sulfate slows down hydrogen productionD:the algae's cells work slowly if there is no oxygen in the air
共用题干第一篇Putting Plants to WorkUsing the power of the sun is nothing new.People have had solar-powered calculators and buildings withsolar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as anenergy source for billions of years.Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化 碳）,and water into sugarsand starche（淀粉）,stored energy that the piants can use. This conversion process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly how plants do it.Some scientists are trying to get plants,or biological cells that act like plants, to work as very small photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient- ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe- sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of the time.Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐） from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air is present.Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work,they may be able to speed the cells' activity and produce larger quantities of hydrogen.The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms." Scientists study how photosynthesis works because they want to_______________.A: improve the efficiency of itB: turn plant sugars to a new form of energyC: get more sugars and starches from plantsD: make green plants a new source of energy
共用题干第一篇Putting Plants to WorkUsing the power of the sun is nothing new.People have had solar-powered calculators and buildings withsolar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as anenergy source for billions of years.Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化 碳）,and water into sugarsand starche（淀粉）,stored energy that the piants can use. This conversion process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly how plants do it.Some scientists are trying to get plants,or biological cells that act like plants, to work as very small photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient- ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe- sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of the time.Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐） from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air is present.Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work,they may be able to speed the cells' activity and produce larger quantities of hydrogen.The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms." How do plants relate to solar energy?A: They have been using it for billions of years.B: They are the real experts in producing it.C: They have been a source of it.D: They have been used to produce it.
共用题干第一篇Putting Plants to WorkUsing the power of the sun is nothing new.People have had solar-powered calculators and buildings withsolar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as anenergy source for billions of years.Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化 碳）,and water into sugarsand starche（淀粉）,stored energy that the piants can use. This conversion process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly how plants do it.Some scientists are trying to get plants,or biological cells that act like plants, to work as very small photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient- ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe- sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of the time.Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐） from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air is present.Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work,they may be able to speed the cells' activity and produce larger quantities of hydrogen.The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms." What does Ghirardi say about algae?A:They can be a good energy source.B:They grow faster in a reactor.C:They will be planted everywhere.D:They are cheap to eat.
Nuclear power plants in Europe have been forced to____electricity production becauseof warmer-than-usual seawater.A、cutinB、cut offC、cut outD、cut back
The revolution of machinery could __________without a new source of both movable and constant power in the new century.A. be born B. not have been born C. have been born D. have born
共用题干Global WarmingFew people now question the reality of global warming and its effects on the world's climate. Many scientists1the blame for recent natural disasters on the increase2the world's temperatures and are convinced that,more than3before,the Earth is at4from the forces of the wind,rain and sun.5to them,global warming is making extreme weather events,6as hurricanes and droughts,even more7and causing sea levels all around the world to8.Environmental groups are putting9on governments to take action to reduce the 10 of carbon dioxide which is given 11 by factories and power plants,thus attacking the problem at its source. They are in12of more money being spent on research into so-lar,wind and wave energy devices,which could then replace existing power13.Some scientists,14believe that even if we stopped releasing carbon dioxide and other gases into the atmosphere tomorrow,we would have to wait15hundred years to notice the results. Global warming,it seems,is here to stay.11._________A: off B: away C: up D: over
共用题干Global WarmingFew people now question the reality of global warming and its effects on the world's climate. Many scientists1the blame for recent natural disasters on the increase2the world's temperatures and are convinced that,more than3before,the Earth is at4from the forces of the wind,rain and sun.5to them,global warming is making extreme weather events,6as hurricanes and droughts,even more7and causing sea levels all around the world to8.Environmental groups are putting9on governments to take action to reduce the 10 of carbon dioxide which is given 11 by factories and power plants,thus attacking the problem at its source. They are in12of more money being spent on research into so-lar,wind and wave energy devices,which could then replace existing power13.Some scientists,14believe that even if we stopped releasing carbon dioxide and other gases into the atmosphere tomorrow,we would have to wait15hundred years to notice the results. Global warming,it seems,is here to stay.2._________A: in B: at C: by D: to
共用题干第一篇Plant GasScientists have been studying natural sources of methane（甲烷，沼气）for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist（地球化学家）at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes（微生物）need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.In its experiments, Keppler's team used sealed chambers（室，房间；腔）that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C.,they found,a gram of dried plant material released up to 3 nanograms（微克）of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数，细菌）that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist（生物地球化学家）at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes.Which of the following about methane is not mentioned in the passage?A:Plants growing in soil release methane.B:Plants growing in water release methane.C:Soil microbes consume methane.D:Microbes in plants produce methane.
共用题干第一篇Plant GasScientists have been studying natural sources of methane（甲烷，沼气）for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist（地球化学家）at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes（微生物）need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.In its experiments, Keppler's team used sealed chambers（室，房间；腔）that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C.,they found,a gram of dried plant material released up to 3 nanograms（微克）of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数，细菌）that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist（生物地球化学家）at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes.Which statement is true of the methane emissions of plants in the experiment?A:The lower the temperature,the higher the amount of methane emissions.B:Living plants release less methane than dried plants at the same temperature.C:When exposed to sunlight,plants stop releasing methane.D:The higher the temperature,the greater the amount of methane emissions.
共用题干“Salty” Rice Plant Boosts HarvestsBritish scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world. Flowers and Yeo have started a program______.A: to find ways to prevent water pollutionB: to identify genes that promote growth in salty soilC: to breed rice plants that taste saltyD: to find ways to remove excessive salt from soil
共用题干“Salty” Rice Plant Boosts HarvestsBritish scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world. Which of the following is NOT mentioned as a cause of the problem discussed in the passage?A: Natural barriers to sea water have been destroyed.B: The water table has gone down after droughts.C: Sea level has been continuously rising.D: Evaporation of water leaves salt behind.
共用题干第一篇Plant GasScientists have been studying natural sources of methane（甲烷，沼气）for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist（地球化学家）at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes（微生物）need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.In its experiments, Keppler's team used sealed chambers（室，房间；腔）that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C.,they found,a gram of dried plant material released up to 3 nanograms（微克）of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数，细菌）that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist（生物地球化学家）at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes.To test whether plants are a source of methane,the scientists created_______.A:an oxygen-free environmentB:an environment with the same concentration of oxygen as the Earth hasC:a carbon dioxide-free environmentD:an environment filled with the greenhouse gas
共用题干Global WarmingFew people now question the reality of global warming and its effects on the world's climate. Many scientists1the blame for recent natural disasters on the increase2the world's temperatures and are convinced that,more than3before,the Earth is at4from the forces of the wind,rain and sun.5to them,global warming is making extreme weather events,6as hurricanes and droughts,even more7and causing sea levels all around the world to8.Environmental groups are putting9on governments to take action to reduce the 10 of carbon dioxide which is given 11 by factories and power plants,thus attacking the problem at its source. They are in12of more money being spent on research into so-lar,wind and wave energy devices,which could then replace existing power13.Some scientists,14believe that even if we stopped releasing carbon dioxide and other gases into the atmosphere tomorrow,we would have to wait15hundred years to notice the results. Global warming,it seems,is here to stay.1._________A: give B: put C: take D: have
共用题干Global WarmingFew people now question the reality of global warming and its effects on the world's climate.Many scientists______(1)the blame for recent natural disasters on the increase______(2) the world's temperatures and are convinced that,more than______(3)before,the Earth is at______(4)from the forces of the wind,rain and sun.______(5)to them,global warming is making extreme weather events,______(6)as hurricanes and droughts,even more______(7)and causing sea levels all around the world to______(8).Environmental groups are putting______(9) on governments to take action to reduce the ______(10) of carbon dioxide which is given______(11) by factories and power plants,thus attacking the problem at its source.They are in______(12) of more money being spent on research into so-lar,wind and wave energy devices,which could then replace existing power______(13).Some scientists,______(14) believe that even if we stopped releasing carbon dioxide and other gases into the atmosphere tomorrow,we would have to wait______(15) hundred years to notice the results.Global warming,it seems,is here to stay.1._________A:giveB:putC:takeD:have
问答题Practice 3 At first, as he adjusted pumps and checked temperatures, Aaron Boucher looked like any technician in the control room of an electrical plant. Then he rushed to the window and scanned the sky, to check his fuel supply. Mr. Boucher was battling clouds, timing the operations of his power plant to get the most out of patchy sunshine. It is a skill that may soon be in greater demand, for the world appears to be on the verge of a boom in a little-known but promising type of solar power. It is not the kind that features shiny panels bolted to the roofs of houses. This type involves covering acres of desert with mirrors that focus intense sunlight on a fluid, heating it enough to make steam. The steam turns a turbine and generates electricity. The technology is not new, but it is suddenly in high demand. As prices rise for fossil fuels and worries grow about their contribution to global warming, solar thermal plants are being viewed as a renewable power source with huge potential. After a decade of no activity, two prototype solar thermal plants were recently opened in the United States, with a capacity that could power several big hotels, neon included, on the Las Vegas Strip, about 20 miles north of here. Another 10 power plants are in advanced planning in California, Arizona and Nevada. On sunny afternoons, those 10 plants would produce as much electricity as three nuclear reactors, but they can be built in as little as two years, compared with a decade or longer for a nuclear plant. Some of the new plants will feature systems that allow them to store heat and generate electricity for hours after sunset. At Nevada Solar One the other day, Mr. Boucher, 30, ran the computerized control room. He was trying to produce as much electricity as possible while saving heat to tide the plant over as clouds cast episodic shadows on the solar array. “I’ve been fighting it all day,” he said. Imperceptibly, in the dusty wind of the high desert, 182,000 mirrors moved from east to west, tracking the sun across the sky.
单选题What is the fourth paragraph of the passage mainly about?AThe ways to use solar power.BThe advantages of solar power.CThe places to build the solar power plants.DThe difficulties of putting solar power to use widely.
单选题Plants use the carbon, along with sunlight, for growth, and （） oxygen into the atmosphere in a process known as photosynthesis.ArelieveBrelateCreleaseDretain