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  3. British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their w

British scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their w

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问题     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【C1】______which genes enable some plants to survive salty conditions. The aim is to breed this【C2】______into crops, starting with rice. It is estimated that each year more than 10m hectares of agricultural land are【C3】______because salt gets into the soil and stunts plants. The problem is caused by several factors. In the tropics, mangroves(红树林)that【C4】______swamps and traditionally formed【C5】______to sea water have been cut down. In the Mediterranean, a series of【C6】______have caused the water table to drop, allowing sea water to seep in. In Latin America, irrigation often causes problems when water is【C7】______by the heat, leaving salt deposits behind. Excess salt then enters the plants and prevents them functioning【C8】______. 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【C9】______use. Once the characteristics for surviving salty soil are known, Flowers and Yeo will try to breed the【C10】______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.
A)evaporated I)create
B)barriers J)capability
C)normally K)establish
D)economic L)ensure
E)excluded M)capacity
F)lost N)commercial
G)droughts O)appropriate
H)perfectly
【C9】
选项
答案N
解析 空前介词及空后名词提示所填词可能为形容词或名词。备选项中的形容词D)economic和N)commercial之间为语义场共现的关系，故二者中很有可能有一个为干扰项。economic强调的是利益，而本句主要是强调新水稻品种的use(用途)，故可将其排除。N)commercial能与use构成搭配，commercial use意为“商业用途”，符合句意。
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