单选题As a gardener, Jim has to water the flowers and ______ the grass in the garden every morning.A trimB improveC refineD repair

共用题干
“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 pollution
B: to identify genes that promote growth in salty soil
C: to breed rice plants that taste salty
D: to find ways to remove excessive salt from soil

共用题干
“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 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.

共用题干
Keeping Cut Flowers（鲜切花）
1. While everybody enjoys fresh cut flowers around his/her house,few people know how to keep them for as long as possible .This may be done by keeping in mind a few simple facts.
2. An important thing to remember about cut flowers is that they are sensitive to temperature.For example,studies have shown that cut carnations（康乃馨）retain their freshness eight times lon-ger when kept at 12℃than when kept at 26℃．Keeping freshly harvested flowers at the right tem-peratures is probably the most important aspect of flower care.
3. Flowers are not intended by nature to live very long.Their biological purpose is simply to at-tract birds or insects,such as bees,for pollination（授粉）.After that,they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide（二氧化碳）, called respiration（呼吸）,generates the energy the flower needs to give the flower its shape and color. The making of seeds also depends on this energy.While all living things respire,flowers have a high level of respiration.A result of all this respiration is heat,and for flowers the level of heat relative to the mass of the flower is very high.Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration,the sooner the flower dies.
4. How,then,to control the rate at which flowers die?By controlling respiration.How is respi-ration controlled?By controlling temperature .We know that respiration produces heat,but the re-verse（相反的过程）is also true. Thus by maintaining low temperatures , respiration is reduced and the cut flower will age more slowly.
5. Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to“drink”water that is dirty or otherwise polluted.Even when water looks and smells clean,it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach（漂白剂）can be used in small quantities.It is recommended that 15 drops of chlorine bleach(at 4%solution)be add-ed to each litre of water. The water and solution should also be replaced each day.

Paragraph 2________
A: Control of Respiration
B: Beauty of Fresh Cut Flowers
C: Role of Respiration
D: Most Important Aspect of Flower Care
E: Need for Cleanwater
F:.Ways of Stopping Respiration

Jim has made up his mind not to go to the meeting.

A: agreed
B: decided
C: promised
D:wanted

共用题干
“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
Keeping Cut Flowers（鲜切花）
1. While everybody enjoys fresh cut flowers around his/her house,few people know how to keep them for as long as possible .This may be done by keeping in mind a few simple facts.
2. An important thing to remember about cut flowers is that they are sensitive to temperature.For example,studies have shown that cut carnations（康乃馨）retain their freshness eight times lon-ger when kept at 12℃than when kept at 26℃．Keeping freshly harvested flowers at the right tem-peratures is probably the most important aspect of flower care.
3. Flowers are not intended by nature to live very long.Their biological purpose is simply to at-tract birds or insects,such as bees,for pollination（授粉）.After that,they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide（二氧化碳）, called respiration（呼吸）,generates the energy the flower needs to give the flower its shape and color. The making of seeds also depends on this energy.While all living things respire,flowers have a high level of respiration.A result of all this respiration is heat,and for flowers the level of heat relative to the mass of the flower is very high.Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration,the sooner the flower dies.
4. How,then,to control the rate at which flowers die?By controlling respiration.How is respi-ration controlled?By controlling temperature .We know that respiration produces heat,but the re-verse（相反的过程）is also true. Thus by maintaining low temperatures , respiration is reduced and the cut flower will age more slowly.
5. Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to“drink”water that is dirty or otherwise polluted.Even when water looks and smells clean,it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach（漂白剂）can be used in small quantities.It is recommended that 15 drops of chlorine bleach(at 4%solution)be add-ed to each litre of water. The water and solution should also be replaced each day.

A few simple facts will help you keep cut flowers________.
A: by keeping its original shape and color
B: in the life of cut flowers
C: to produce carbon dioxide
D: for as long as possible
E: by controlling temperature
F: to replace the water and solution every day

共用题干
Keeping Cut Flowers（鲜切花）
1. While everybody enjoys fresh cut flowers around his/her house,few people know how to keep them for as long as possible .This may be done by keeping in mind a few simple facts.
2. An important thing to remember about cut flowers is that they are sensitive to temperature.For example,studies have shown that cut carnations（康乃馨）retain their freshness eight times lon-ger when kept at 12℃than when kept at 26℃．Keeping freshly harvested flowers at the right tem-peratures is probably the most important aspect of flower care.
3. Flowers are not intended by nature to live very long.Their biological purpose is simply to at-tract birds or insects,such as bees,for pollination（授粉）.After that,they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide（二氧化碳）, called respiration（呼吸）,generates the energy the flower needs to give the flower its shape and color. The making of seeds also depends on this energy.While all living things respire,flowers have a high level of respiration.A result of all this respiration is heat,and for flowers the level of heat relative to the mass of the flower is very high.Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration,the sooner the flower dies.
4. How,then,to control the rate at which flowers die?By controlling respiration.How is respi-ration controlled?By controlling temperature .We know that respiration produces heat,but the re-verse（相反的过程）is also true. Thus by maintaining low temperatures , respiration is reduced and the cut flower will age more slowly.
5. Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to“drink”water that is dirty or otherwise polluted.Even when water looks and smells clean,it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach（漂白剂）can be used in small quantities.It is recommended that 15 drops of chlorine bleach(at 4%solution)be add-ed to each litre of water. The water and solution should also be replaced each day.

Respiration plays a key role________.
A: by keeping its original shape and color
B: in the life of cut flowers
C: to produce carbon dioxide
D: for as long as possible
E: by controlling temperature
F: to replace the water and solution every day