再问og 135，请NN解惑

spritejudy

134. 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. C

Since the enzyme kills caterpillars of all species, spraying croplands might not be advisable if caterpillars of beneficial insect species would also be killed. According to choice C, there are many such beneficial species. Choice C thus supports the view that spraying would be inadvisable and is the best answer.

 

Choice A is incorrect because spraying, if effective, would make natural predation irrelevant. Choice B is incorrect because the existence of pests that the spraying inadvisable. Choice D and E each raise a point concerning details of how and when spraying programs might be implemented, without challenging the advisability of such programs. Both choices are therefore incorrect.

知道C是肯定对的了，但是本来我选的是E，看解释说E没有反对program的advisablity，这个advisabilty是什么意思啊？

希望能很清楚地明白为什么E不对吧，谢谢NN们了！！！

wencui0602

我不是NN，不过我也说说我的理解，希望对楼主有帮助

advisability在这里是指方法的有效性，即是否可以达到目的，而目的题目已经说得很清楚了，是 eradicate agricultural pests that go through a caterpillar stage ，而E选项说的是enzyme的生产情况，和是否有助于消除害虫没有关系，是无关选项

spritejudy

恩，wencui说的有理，NN,NN