Scientists are working to develop crop plants that can reduce the amount of water used for agriculture. Almost sixty percent of the world’s freshwater withdrawals from rivers, lakes and other water r 题目和参考答案——青夏教育精英家教网—

题目内容

Scientists are working to develop crop plants that can reduce the amount of water used for agriculture. Almost sixty percent of the world’s freshwater withdrawals from rivers, lakes and other water resources go toward irrigating fields.

Scientists are using biotechnology as well as traditional breeding methods to develop water-saving crops to feed a growing world.

Thomas “Tommy” Carter is a plant scientist in North Carolina. He works for the Agricultural Research Service in the United States Department of Agriculture. He leads Team Drought, a group of researchers at five universities. They have been using conventional breeding methods to develop and test soybeans that can grow well under dry conditions.

Tommy Carter started working on drought-resistant soybeans in 1981. His research has taken him as far as China, where soybeans have been grown for thousands of years.

Farmers in the United States, however, have grown soybeans for only about a century. Tommy Carter says the soybeans they grow are for the most part genetically similar. More differences could better protect crops against climate changes that can reduce production. Those changes include water shortages which could increase from global warming.

The Agriculture Department has a soybean germplasm(胚质) collection, a collection of genetic material passed from one generation to the next. Members of Team Drought studied more than 2,500 examples from the collection.

They looked at ones from the home of soybeans, Asia. They searched for germplasms that could keep plants from weakening and wilting (凋谢)during hot, dry summers in the United States.

Tommy Carter says they found only five. But these slow-wilting lines, he says, produce four to eight bushels（英斗）more than normal soybeans under drought conditions. The yield depends on location and environment.

Scientists are also working on other plants that either use less water or use it better, or both. For example, companies like Monsanto, DuPont and Syngenta have been developing corn with reduced water needs. Monsanto expects to be ready in a few years to market its first corn seeds genetically engineered to resist drought.

1. According to the passage, scientists try to find out how to _______.

A. grow crops with less water

B. increase crop production

C. feed a growing world

D. save the world’s water resource

2. Why did Tommy Carter come to China?

A. He likes traveling.

B. China has a long history.

C. He’s doing research into soybeans.

D. He works for the Agricultural Research Service.

3. What’s inferred from the passage?

A. Climate changes lead to global warming.

B. Water shortages contribute to global warming.

C. Genetically different soybeans need much water to grow.

D. Genetically different soybeans help to fight against damaging climate changes.

4. What do we know about slow-wilting plants talked about in the passage?

A. They yield big profits.

B. They can grow in almost any climate.

C. They seem to be drought-resistant.

D. They need much water for their growth.

【小题1】A

【小题2】C

【小题3】D

【小题4】C

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Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU) researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

“To provide enough power, we need certain methods with high energy density(密度)”，said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope(放射性同位素) battery can provide power density that is much higher than chemical batteries.”

Kwon and his research team have been working on building a small nuclear battery, presently the size and thickness of a penny, intended to power various micro / nanoelectromechanical systems (M/NEMS). Although nuclear batteries can cause concerns, Kwon said they are safe.

“People hear the word ‘nuclear’ and think of something very dangerous,” he said, “However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems.”

His new idea is not only in the battery’s size, but also in its semiconductor(半导体). Kwon’s battery uses a liquid semiconductor rather than a solid semiconductor.

“The key part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure(晶体结构) of the solid semiconductor,” Kwon said, “By using a liquid semiconductor, we believe we can minimize that problem.”

Together with J. David Robertson, chemistry professor and associate director of the MU Research Reactor, Kwon is working to build and test the battery. In the future, they hope to increase the battery’s power, shrink its size and try with various other materials. Kwon said that battery could be thinner than the thickness of human hair.

Which of the following is true of Jae Kwon?

A. He teaches chemistry at MU.

B. He developed a chemical battery.

C. He is working on a nuclear energy source.

D. He made a breakthrough in computer engineering.

Jae Kwon gave examples in Paragraph 4_________.

A. to show chemical batteries are widely applied.

B. to introduce nuclear batteries can be safely used.

C. to describe a nuclear-powered system.

D. to introduce various energy sources.

Liquid semiconductor is used to _________.

A. get rid of the radioactive waste

B. test the power of nuclear batteries.

C. decrease the size of nuclear batteries

D. reduce the damage to lattice structure.

According to Jae Kwon, his nuclear battery _______.

A. uses a solid semiconductor

B. will soon replace the present ones.

C. could be extremely thin

D. has passed the final test.

The text is most probably a ________.

A. science news report B. book review

C. newspaper ad D. science fiction story

PART FOUR WRITING (45%)

The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.

A. what B. which C. that D. though

People diet to look more attractive. Fish diet to avoid being beaten up, thrown out of their social group, and getting eaten as a result. That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists.

The research team have discovered that subordinate fish voluntarily diet to avoid challenging their larger competitors. “In studying gobies we noticed that only the largest two individuals, a male and female, had breeding(繁殖) rights within the group," explains Marian Wrong. “All other group members are nonbreeding females, each being 5-10% smaller than its next largest competitor. We wanted to find out how they maintain this precise size separation."

The reason for the size difference was easy to see. Once a subordinate fish grows to within 5-10% of the size of its larger competitor, it causes a fight which usually ends in the smaller goby being driven away from the group. More often than not, the evicted fish is then eaten up.

It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish. Whether they did so voluntarily, by restraining how much they ate, was not clear. The research team decided to do an experiment. They tried to fatten up some of the subordinate gobies to see what happened. To their surprise, the gobies simply refused the extra food they were offered, clearly preferring to remain small and avoid fights, over having a feast.

The discovery challenges the traditional scientific view of how boss individuals keep their position in a group. Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves, so keeping their competitors small.

While the habits of gobies may seem a little mysterious. Dr. Wong explains that understanding the relationships between boss and subordinate animals is important to understanding how hierarchical(等级的) societies remain stable.

The research has proved the fact that voluntary dieting is a habit far from exclusive to human.”As yet, we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature," the researchers comment. “Data on human dieting suggests that, while humans generally diet to improve health or increase attractiveness, rarely does it improve long-term health and males regularly prefer females that are fatter than the females' own ideal."

65 When a goby grows to within 5-10% of the size of its larger competitor, it ______.

A. faces danger B. has breeding rights

C. eats its competitor D. leaves the group itself

66. The underlined words “the evicted fish" in Paragraph 3 refer to _____.

A. the fish beaten up B. the fish found out

C. the fish fattened up D. the fish driven away

67 The experiment showed that smaller fish ____.

A. fought over a feast B. went on diet willingly

C. preferred some extra food D. challenged the boss fish

68. What is the text mainly about?

A. Fish dieting and human dieting.

B. Dieting and health.

C. Human dieting.

D. Fish dieting.

What makes a person a scientist? Does he have ways or tools of learning that are different from those of others??The answer is“no”.It isn't the tools a scientist uses but how he uses these tools which makes him a scientist .You will probably agree that knowing how to use a power is important to a carpenter（木匠）.You will probably agree,too, that knowing how to investigate（调查）,how to discover information ,is important to everyone. The scientist ,however ,goes one step further ;he must be sure that he has a reasonable answer to his questions and that his answer he gets to many questions is into a large set of ideas about how the world works.?

The scientist's knowledge must be exact .There's no room for half right or right just half the time. He must be as nearly right as the conditions permit .What works under one set of conditions at one time must work under the same conditions at other times. If the conditions are different ,any changes the scientist observes in a demonstration（实证）must be explained by the changes in the conditions. This is one reason why investigations are important in science .Albert Einstein ,who developed the Theory of Relativity ,arrived at this theory through mathematics. The accuracy（正确性）of his mathematics was later tested through investigation. Einstein's ideas were proved to be correct .A scientist uses many tools for measurements .Then the measurements are used to make mathematical calculations（计算）that may test his investigations.

1.What makes a scientist according to the passage??

A.The tools he uses.

B.His ways of learning.?

C.The way he uses his tools.

D.The various tools he uses.?

2.“...knowing how to investigate ,how to discover information ,is important to everyone.”The writer says this to show_______.?

A.the importance of information

B.the difference between scientists and ordinary people?

C.the importance of thinking

D.the difference between carpenters and ordinary people?

3.A sound scientific theory should be one that_______.?

A.works under one set of conditions at one time and also works under the same conditions at other times?