共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.The shoot system of perennials can help the plants absorb less of the sun's ray.A:Right B:Wrong C:Not mentioned
共用题干
Plants in Desert
Only special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.
The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time.
The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.
Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.
Plants in Desert
Only special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.
The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time.
The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.
Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.
The shoot system of perennials can help the plants absorb less of the sun's ray.
A:Right
B:Wrong
C:Not mentioned
A:Right
B:Wrong
C:Not mentioned
参考解析
解析：根据第一段第一句可知，只有特殊的植物才能在沙漠中存活，这是因为沙漠中土壤的温度过高，每年的温度能达到75℃以上，而并不是因为沙漠中的气候变化多端。
根据线索词“Grasses and flowers”和“see1seeas"，可以很快把第二段第一句确定为答案相关句。这个句子的大意是：沙漠里的花草年复一年以种子的形式度过漫长、炎热，而又干燥的季节。可见题干的说法与原文的说法一致，所以选择A项。
题干的大意是：沙漠里春季的雨水很快会消失，而沙漠里生命周期短的花草能够适应这一环境特点。利用题干中的“life cycles”作为线索词，可以很快把第二段第四、五句确定为答案相关句，这两句话表明，生命周期短能帮助植物在沙漠中存活，因为春季的雨水消失后，这些植物将不再需要雨水。可见题干的说法与原文的说法一致。
本篇文章并未提到冬天里花草最难生存，所以选择C项。
利用题干中的“The shoot system”作为线索词，可以把第三段最后一句确定为答案相关句。这句话表明，茎轴系统极大地限制了蒸发所带来的水分损失，而不是说茎轴系统能减少植物对太阳光线的吸收。可见题干与原文的说法不符。
倒数第二段的主题句是第一句，讲述的主要是沙漠多年生植物能生存的原因。题干表述正确，所以选择A项。
根据题干中的线索词“lose their leaves1 "，不难把最后一段第一、二句确定为答案相关句。这两句话表明，沙漠多年生植物和较湿润地区的树木落叶的原因是一样的，都是为了减少水分的蒸发。
根据线索词“Grasses and flowers”和“see1seeas"，可以很快把第二段第一句确定为答案相关句。这个句子的大意是：沙漠里的花草年复一年以种子的形式度过漫长、炎热，而又干燥的季节。可见题干的说法与原文的说法一致，所以选择A项。
题干的大意是：沙漠里春季的雨水很快会消失，而沙漠里生命周期短的花草能够适应这一环境特点。利用题干中的“life cycles”作为线索词，可以很快把第二段第四、五句确定为答案相关句，这两句话表明，生命周期短能帮助植物在沙漠中存活，因为春季的雨水消失后，这些植物将不再需要雨水。可见题干的说法与原文的说法一致。
本篇文章并未提到冬天里花草最难生存，所以选择C项。
利用题干中的“The shoot system”作为线索词，可以把第三段最后一句确定为答案相关句。这句话表明，茎轴系统极大地限制了蒸发所带来的水分损失，而不是说茎轴系统能减少植物对太阳光线的吸收。可见题干与原文的说法不符。
倒数第二段的主题句是第一句，讲述的主要是沙漠多年生植物能生存的原因。题干表述正确，所以选择A项。
根据题干中的线索词“lose their leaves1 "，不难把最后一段第一、二句确定为答案相关句。这两句话表明，沙漠多年生植物和较湿润地区的树木落叶的原因是一样的，都是为了减少水分的蒸发。
相关考题：
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
23． From the passage，we can know it is ________for plants to grow in dry places．A． easyB． difficultC． impossibleD． important
BScientists are trying to make the deserts into good land again． They want to，bring water to the deserts． But more and more places of the earth is becoming deserts all the time， Scientists may not be able to change the deserts． Scientists think that people make deserts． People are do-ing bad things to the earth．Some places on the earth don-t get very much rain． But they still don-t become deserts．This is because some green plants are growing there． Small green plants and grass are very helpful to dry places． Plants don't let the wind blow the earth away． When 8 little bit of rain falls，the plants hold the water． Without plants，the land can become a desert much more easily．( )26． Why can the land become a desert?A． Because some places don't get very much rain．B． Because plants don-t let the hot sun make the earth even drier．C． Because people don't keep the earth well．D． Because scientists haven-t learnt enough about the deserts．
29． Why are green plants and grass helpful?A． Because they can hold the water．B． Because they can stop the wind from blowing the earth away．C． Because they can keep the earth wet．D．All the above．
共用题干第三篇Only special plants can survive in the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃.Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long, hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time that the water from the spring rains disappears—ust a few weeks after it falls一such plants no longer need any.The perennials（多年生植物）have special features which enable them to survive as plants for several years. Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in a short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season.Then,in the next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.We can learn from the passage that the shoot system of the perennials_________.A:can help the perennials absorb less of the sun's rayB:decides the appearance of the perennials in desertC:limits the function of the perennials' branchesD:may prevent the perennials from losing much water
共用题干第三篇Only special plants can survive in the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃.Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long, hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time that the water from the spring rains disappears—ust a few weeks after it falls一such plants no longer need any.The perennials（多年生植物）have special features which enable them to survive as plants for several years. Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in a short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season.Then,in the next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.According to the passage,spring is the best time for plants in desert_________.A:to find a shady placeB:to get water for their growthC:to reduce water lossD:to enjoy the sunshine
共用题干第三篇Only special plants can survive in the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃.Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long, hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time that the water from the spring rains disappears—ust a few weeks after it falls一such plants no longer need any.The perennials（多年生植物）have special features which enable them to survive as plants for several years. Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in a short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season.Then,in the next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Some grasses and flowers can survive in the desert because__________.A:they need little water for their survivalB:they bear long roots and the seeds are fit for dry weatherC:they stay in the form of seeds to wait for the right armiount of waterD:with long roots,they do not depend on the rain to get enough water
共用题干第三篇Only special plants can survive in the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃.Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long, hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time that the water from the spring rains disappears—ust a few weeks after it falls一such plants no longer need any.The perennials（多年生植物）have special features which enable them to survive as plants for several years. Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in a short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season.Then,in the next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Ordinary plants can not survive the desert weather as a result of the following except for_________.A:the strong windsB:the strong sun's rayC:the long summer daysD:the high soil temperature
共用题干第三篇Only special plants can survive in the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃.Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds which drive small-sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long, hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time that the water from the spring rains disappears—ust a few weeks after it falls一such plants no longer need any.The perennials（多年生植物）have special features which enable them to survive as plants for several years. Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in a short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many desert perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter. This reduces their water loss by evaporation during the dry season.Then,in the next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.The last paragraph is mainly about__________.A:the comparison between plants in different areasB:the growth of new leaves in the rainy seasonC:water loss by evaporation in the dry seasonD:the changes in the leaves of the perennials
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring.Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time.The small shoot system,on the other hand,considerably limits water loss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.A:Right B:Wrong C:Not mentioned
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Grasses and flowers in the desert whose life cycles are short show their ability to adapt to the quick disappearance of rainwater there after it falls in spring.A:Right B:Wrong C:Not mentioned
Geothermal(地热)Energy 1 Since heat naturally moves from hotter regions to cooler ones, the heat from the earth's center flows outwards towards the surface. In this way, it transfers to the next layer of rock. If the temperature is high enough, some of this rock melts and forms magma(岩浆). The magma ascends in its turn towards the earth's surface. It often remains well below the earth's surface, creating vast areas of hot rock. In such regions, there are deep cracks, which allow rainwater to descend underground. Some of the heated rainwater travels back up to the earth's surface where it will appear as a hot spring. However, if this ascending hot water reaches a layer of impermeable(不可渗透的)rock, it remains trapped, forming a geothermal reservoir. If geothermal reservoirs are close enough to the surface, they can be reached by drilling wells. Hot water and steam shoot up the wells naturally, and can be used to produce electricity in geothermal power plants. 2.A few geothermal power plants depend on dry-stem reservoirs which produce steam but little or no water. In these cases, the steam is piped up directly to provide the power to spin a turbine generator. The first geothermal power plant, constructed at Lardarello in Italy, was of this type, and is still producing electricity today. 3.Most currently operating geothermal power plants are either "flash" steam plants or binary(双重的)plants. Flash plants produce mainly hot water ranging in temperature from 300° to 700°Fahrenheit. This water is passed through one or two separators where released from the pressure of the underground reservoir, it "flashes" or boils into steam Again, the force of this steam provides the energy to spin the turbine and produce electricity. The geothermal water and steam are then reinjected directly back down into the earth to maintain the volume and pressure of the reservoir. Gradually they will be reheated and can then be used again. 4.A reservoir with temperatures below 300° Fahrenheit is not hot enough to flash steam but it can still be used to generate electricity in binary fluid. The steam from this is used to power the turbines. As in the flash steam plant, the geothermal water is recycled back into the reservoir.文章(23~30)Paragraph1_____A.Dry steam plantsB.Binary plantsC.Origin of geothermal energyD.Generation of electricityE.Flash steam plantsF.Recyclable water and steam
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Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Ordinary plants are unable to survive in the desert mainly because of the changeable weather.A:Right B:Wrong C:Not mentioned
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.The shoot system of perennials can help the plants absorb less of the sun's ray.A:Right B:Wrong C:Not mentioned
共用题干Ecosystem1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.To protect our ecosystems we should not use more than______.A: our share of resourcesB: a biological creatureC: a given areaD: the maintenance of the ecosystemE: the source of foodF: various species
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Winter is the toughest season for the grasses and flowers to surviVe.A:Right B:Wrong C:Not mentioned
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.The theme of the second last paragraph is why the perennials can survive as plants for several years.A:Right B:Wrong C:Not mentioned
共用题干Ecosystem1. The word “ecosystem” is short for ecological（生态的）system. An ecosystem is where living creatures expand within a given area. You can say that an ecosystem is the natural environment where biological organisms（生物）such as plants,animals and humans co-exist in this world. So naturally that includes you and me. Yes,we are all members of an ecosystem!2 .There are different kinds of ecosystems depending on the type of surface or environ-ment. Most are naturally made such as the ocean or lake and the desert or rainforest.Some are man-made or artificial to encourage co-habitation（同居）between living and non-living things in a monitored environment,such as a zoo or garden.3 .Plants make up the biggest group of biological creatures within an ecosystem,and that's because they are the natural food producers for everyone. Plants raised in the earth need air and collect sunlight to help them grow. When they grow,the plants and its fruits or flowers eventually become a source of food to animals,microorganisms（微生物）and even hu- mans,of course. Food is then converted to energy for the rest of us to function,and this hap-pens in a never-ending cycle until the living creatures die and break up back in the earth.4 .Ecosystems are the basis of survival for all living things.We depend on plants and ani-mals for food. In order for us to exist,we need to grow and care about other organisms. We also need to care for the non-living things within our environment like our air and water so we can continue living as a population. Since plants,animals and humans are all of various species（物种）,we all play a role in maintaining the ecosystem.5 .To preserve our ecosystems,we should stop using too much energy,which happens when we consume more than our share of resources. Humans should not disturb the natural habitat（栖息地）of plants and animals,and allow them to grow healthily for the cycle to con-tinue. Too many people in a habitat can mean displacement（搬迁）: imagine being thrown out of your home because there is no more space for everyone. Worse,overpopulation can also ru- in the environment and cause destruction of existing plants and animals.Paragraph 2_________A: What Can We Do to Help Protect Ecosystems?B: What Are Different types of Ecosystems?C: What Is an Ecosystem?D: What Destroys Ecosystems?E: How Does an Ecosystem Work?F: Why Are Ecosystems Emportant?
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Desert perennials lose their leaves after the rainy season just as trees in wetter climates lose theirs because winter arrives,but the reasons for this feature are different.A:Right B:Wrong C:Not mentioned
共用题干Plants in DesertOnly special plants can survive the terrible climate of a desert,for these are regions where the annual range of the soil temperature can be over 75℃．Furthermore,during the summer there are few clouds in the sky to protect plants from the sun's ray.Another problem is the fact that there are frequently strong winds that drive small,sharp particles of sand into the plants,tearing and damaging them.The most difficult problem for all forms of plant life,however,is the fact that the entire annual rainfall occurs during a few days or weeks in spring. Grasses and flowers in desert survive from one year to the next by existing through the long,hot,dry season in the form of seeds.These seeds remain inactive unless the right amount of rain falls.If no rain falls,or if insufficient rain falls,they wait until the next year,or even still the next.Another factor that helps these plants to survive is the fact that their life cycles are short.By the time the water from the spring rains disappears-just a few weeks after it falls-such plants no longer need any.The perennials（多年生植物）have special features that enable them to survive as plants for several years.Thus,nearly all desert perennials have extensive root systems below ground and a small shoot system above ground.The large root network enables the plant to absorb as much water as possible in short time. The small shoot system,on the other hand,considerably limits water ioss by evaporation（蒸发）.Another feature of many perennials is that after the rainy season they lose their leaves in preparation for the long,dry season,just as trees in wetter climates lose theirs in preparation for the winter.This reduces their water loss by evaporation during the dry season.Then,in next rainy season,they come fully alive once more,and grow new branches,leaves and flowers,just as the grasses and flowers in desert do.Grasses and flowers in desert are able to survive because they stay in the form of seeds to wait for the right amount of water to come.A:Right B:Wrong C:Not mentioned
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
共用题干第三篇Citizen ScientistsUnderstanding how nature responds to climate change will require monitoring key life cycle events一 flowering,the appearance of leaves and the first frog calls of the spring一all around the world.But ecologists can't be everywhere so they're turning to non-scientists,sometimes called citizen scientists,for help.Climate scientists are not present everywhere.Because there are so many places in the world and not enough scientists to observe all of them,they're asking for your help in observing signs of climate change across the world.The citizen scientist movement encourages ordinary people to observe a very specificresearch interest一birds,trees,flowers budding,etc.and send their observations to a giant database to be observed by professional scientists.This helps a small number of scientists track a large amount of data that they would never be able to gather on their own.Much like citizen journalists helping large publications cover a hyper-local beat,citizen scientists are ready for the conditions where they live in.All that's needed to become one is a few minutes each day or each week to gather data and send them in.A group of scientists and educators launched an organization last year called the National Phenology Network."Phenology"is what scientists call the study of the timing of events in nature.One of the group's first efforts relies on scientists and non-scientists alike to collect data about plant flowering and leafing eveiy year.The program,called Project BudBurst,collects life cycle data on a variety of common plants from across the United States.People participating in the project一which is open to every- one一record their observations on the Project BudBurst website."People don't have to be plant experts一they just have to look around and see what's in their neighbor- hood,"says Jennifer Schwartz,an education consultant with the project."As we collect these data,we'll be able to make an estimate of how plants and communities of plants and animals will respond as the climatechanges."What is the final purpose of Project BudBurst?A:To study when plants will have their first buds.B:To find out the types of plants in the neighborhood.C:To collect life cycle data on a variety of common plants from across the United States.D:To investigate how plants and animals will respond as the climate changes.
单选题Some people argue that it would do more harm than good for plants and animals to develop through artificial selection. Which statement best supports this argument?ARoses no longer smell like roses.BPurebred dogs are disappearing.CHumans are harmful agents of plant and animal evolution.DMany domesticated plants and animals can no longer survive in the wild.
多选题Consider each of the choices separately and select all that apply. Which of these can be inferred from the fact that the French built orangeries for certain tropical plants?AGreenhouses may be used to keep plants at a moderate temperatureBThe climate of France is unsuited to growing tropical plants outdoors.CLouis ⅩⅣ was a frequent and enthusiastic traveler to Africa and Asia
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.