第1題
Cactuses(仙人掌)live in dry areas. They may not get much water where they live. The cactus' long roots lie near the surface of the ground. They can get water from desert rains. And since the roots have bark (皮)covering them, they can absorb the water fast. Because the cactus has no leaves, it seems to do the job of making food for the plant and of storing it than out, not much of the plant faces the direct drying sunlight. These broad stems have a great deal of room for storing the water and a thick covering for protecting it. The plant's sharp, pointed needles (針) keep animals from sucking its liquid. However, cactus plants have saved the lives of people in the desert.
_________of the cactus take in water.
A.The leaves
B.The stems
C.The needles
D.The roots
第2題
Trees catch and【C6】______rainwater. Their leaves break the impact【C7】______the rains, robbing them of【C8】______destructive power. The roots of trees allow the water to go into the soil,【C9】______gradually releases it to flow down rivers and refill ground-water reserves. Where there are no【C10】______, the rains run in sheets of water off the land,【C11】______the soil with there Land【C12】______with trees and other plants【C13】______20 times more rainwater than【C14】______earth. As they grow, trees absorb carbon dioxide, the main【C15】______of the "greenhouse effect", which【C16】______irreversibly to change the world's climate. Together, the world's trees, plants and soils contain three times as much carbon as【C17】______is in the atmosphere.
The world's forests【C18】______the vast majority of its animal and plant species. The tropical rainforests【C19】______have well over half of them,【C20】______they cover only about 6% of the Earth's land surface.
【C1】
A.for
B.from
C.by
D.with
第3題
Much of the energy that comes from the sun never reaches the earth's surface. It is either reflected or absorbed by the gases in the upper atmosphere. Of the energy that reaches the lower atmosphere, 30% is reflected by clouds or the earth's surface. The remaining 70% warms the surface of the planet, causes water to evaporate, and provides energy for the water cycle and weather. Only a tiny part, approximately 0.023%, is actually used by green plants to produce food.
Many gases found in the atmosphere actually reflect heat energy escaping from the earth's surface back to the earth. These gases act like the glass of a greenhouse in that they allow energy from the sun to enter but prevent energy form. leaving. They are therefore called greenhouse gases.
When sunlight strikes an object, some of the energy is absorbed and some is reflected. The amount reflected depends on the surface. Dark-colored surfaces, such as dark soil or forest, absorb more energy.
According to the passage, the root cause for weather changes on the earth is
A.the atmosphere surrounding the earth
B.water from oceans and lakes
C.energy from the sun
D.greenhouse gases in the sky
第4題
Much of the energy that comes from the Sun never reaches the Earth's surface. It is either reflected or absorbed by the gases in the upper atmosphere. Of the energy that reaches the lower atmosphere, 30% is reflected by clouds or the Earth's surface. The remaining 70% warms the surface of the planet, causes water to evaporate, and provides energy for the water cycle and weather. Only a tiny part, approximately 0.023%, is actually used by green plants to produce food.
Many gases found in the atmosphere actually reflect heat energy escaping from the Earth's surface back to the Earth. These gases act like the glass of a greenhouse in that they allow energy from the Sun to enter but prevent energy from leaving. They are therefore called greenhouse gases.
When sunlight strikes an object, some of the energy is absorbed and some is reflected. The amount reflected depends on the surface. For example, you've probably noticed how bright snow is when sunlight falls on it. Snow reflects most of the energy from the Sun, so it contributes to the low temperatures of winter. Dark-colored surfaces, such as dark soil or forest, absorb more energy and help warm the surrounding air.
What is the major source of evaporation of water from the oceans and lakes?
A.The moon.
B.The sun.
C.The star.
D.The earth.
第5題
Plants in Desert
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.
Crasses 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--just a few weeks after it falls--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 (蒸發(fā))。
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 winds
B.the strong sun's ray
C.the long summer days
D.the high soil temperature
第6題
Plants in Desert
Only special plants can survive the terrible climate of a desert, for these are regions when the annual range of the soil temperature can be over 75℃. Furthermore, during the summer there are few clouds in the sky to protect plans 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,earing and damaging them. The most difficult probiem 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 fight 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.
Another feature of many perennials is that after the rainy season they 10se 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 (蒸發(fā)) duing 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
第7題
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 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—just a few weeks after it falls—such plants no longer need any.
The perennials 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.
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 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
第8題
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 100 hectares (公頃) of agricultural land are lost because salt gets into the soil and stunts (妨礙生長(zhǎng))plants. The problem is caused by several factors. In the tropics, mangroves (紅樹(shù)林) that create swamps (沼澤) 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 (滲透) in. in Latin America, irrigation often causes problems when water is evaporated (蒸發(fā)) 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 nature will then be able to bloom again, providing much needed food in the poorer countries of the world.
第11題:Which of the following statements about Flowers and Yeo is true?
A.They are students at Sussex University.
B.They are rice breeders.
C.They are husband and wife
D.They are colleagues at an institution of higher learning.
第9題
"Salty" Rice Plant Boosts Harvests
British 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 (公頃) of agricultural land are lost because salt gets into the soil and stunts (妨礙生長(zhǎng)) plants. The problem is caused by several factors. In the tropics, mangroves (紅樹(shù)林) that create swamps (沼澤) 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 (滲透) in. In Latin America, irrigation often causes problems when water is evaporated (蒸發(fā)) 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 nature will then be able to bloom again, providing much needed food in the poorer countries of the world.
Which of the following statements about Flowers and Yeo is true?
A.They are students at Sussex University.
B.They are rice breeders.
C.They are husband and wife.
D.They are colleagues at an institution of higher learning.
第10題
"Salty" Rice Plant Boosts Harvests
British 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 (公頃) of agricultural land are lost because salt gets into the soil and stunts (妨礙生長(zhǎng)) plants. The problem is caused by several factors. In the tropics, mangroves (紅樹(shù)林) that create swamps (沼澤) 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 (滲透) in. In Latin America, irrigation often causes problems when water is evaporated (蒸發(fā)) 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 nature will then be able to bloom again, providing much needed food in the poorer countries of the world.
Which of the following statements about Flowers and Yeo is true?
A.They are students at Sussex University.
B.They are rice breeders.
C.They are husband and wife.
D.They are colleagues at an institution of higher learning.