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  3. Many experts who favor genetically modified foods believe that genetic engineering can help to meet the demands of the world’s i

Many experts who favor genetically modified foods believe that genetic engineering can help to meet the demands of the world’s i

admin2009-04-23  32
问题 Many experts who favor genetically modified foods believe that genetic engineering can help to meet the demands of the world’s increasing population.
Among all the GM crops, Bt genes have proved most effective in ______ when the largest reduction in pesticide use has been reported.
选项
答案cotton
解析 文章里有这样的表述: "of all the crops carrying Bt genes, cotton has brought the biggest drop in pesticide"，而后文章里有具体的种植事例来加以证明：根据美国环保署的资料,1999年大量种植Bt棉花的各州，杀虫剂的喷洒量比往常减少了21%。环保署病虫害防治部门的行政人员Johnson说，那个数字“非常戏剧性，让人印象深刻”。通常在一个生长季中，农人要在棉花田里喷洒7～14次杀虫剂，“如果你种的是Bt棉花，你或许只需施用少量刺鼻的化学药剂，甚至根本就用不着了!而对于其他的作物农药用量较少的现象，文章里面的观点是“这两种作物的农药用量本来就比较少，而且它们所遭受的虫害不一定严重。”
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