British scientists are breeding a new generation of rice plants that will be abl

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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 farms 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 pairs 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 10 million hectares (公顷) of agricultural land are lost because salt gets into the soil and stunts(防碍生长) plants. The problem is caused by several factors. In the tropics, mangroves 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 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 for the poorer countries of the world.
4. Which of the following statements about Flowers and Yeo is true?
A. They are students at Sussex University.  B. They are rice breeders.
5. 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.
6. The word "affect" in Paragraph 5 could be best replaced by________.
A. influence               B. effect               C. stop                    D. present
7. The attitude of the author towards the research project is________.
A. positive                B. negative            C. suspicious             D. indifferent

答案

4-7  DCAA

解析

4.  推断题。从第二段中的Tim Flowers and Tony Yeo，from Sussex University’s School of Biological Sciences，have spent several Years researching how crops，可知，他们是来自大学的老师，他们是搭档，而不是夫妻，所以可以排除A项和C项；B项的意思更不正确。
5.  细节题。A项内容与文章中的traditionally formed barriers to sea water have been cut down一致，B项内容与文章中的a series of droughts have caused the water table to drop一致，D项内容与文章中的when water is evaporated by the heat一致，而C项内容在文章中根本没有谈到。
6.  词义题。我们可以根据句子的意思作出推断。
7.  推断题。从文章最后一段可以看出，作者对这种实验是“肯定的”。主要表现在Land that has been abandoned to nature will then be able to. bloom again，providing much needed food for the poorer countries of the world，作者认为如果该实验成功的话，废弃的土地又会肥沃起来。