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标题: 已解答cxd书上的 support谢谢 [打印本页]

作者: w2222w 时间: 2008-3-20 18:46
标题: 已解答cxd书上的 support谢谢

Caterpillars of all species produce an identical hormone called "juvenile hormone" that maintains feeding behavior. Only when a caterpillar has grown to the right size for pupation to take place does a special enzyme halt the production of juvenile hormone. This enzyme can be synthesized and will, on being ingested by immature caterpillars, kill them by stopping them from feeding.

Which of the following, if true, most strongly supports the view that it would not be advisable to try to eradicate agricultural pests that go through a caterpillar stage by spraying croplands with the enzyme mentioned above?
(A) Most species of caterpillar are subject to some natural predation.
(B) Many agricultural pests do not go through a caterpillar stage.
(C) Many agriculturally beneficial insects go through a caterpillar stage.
(D) Since caterpillars of different species emerge at different times, several sprayings would be necessary.
(E) Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as yet.

目的通过撒药杀死害虫哪个不可行?

e不可行呀药不能大量造.很清晰么

c可能杀死益虫(跟杀害虫没关系一起死么)

为什么答案是c不是e呢搞不懂

[此贴子已经被作者于2008-3-21 9:14:19编辑过]

作者: neo1001 时间: 2008-3-20 21:02
C说的是这样做会把益虫也杀掉，所以这就是not advisable to try to....（因为原文提到的方法不能区分益虫和害虫，这种一网打尽的方法会把益虫也杀掉，所以不advisable）

E说得，不能大规模生产，无关，因为人家说的是“是否advisable to try to...”，人家并没有问是不是feasible

作者: w2222w 时间: 2008-3-21 09:14

哦还真是 advisable可取的;适当的;明智的

问题出在对英语理解上，看来还要加强单词阅读呀

谢谢

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