OG12 115

adolfgao

115. 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.

答案选C
感觉OG的解释也很牵强啊....
哪位大侠进来把题干和答案都解释一下的

tania_zhang

题干是所有物种的毛虫都会有这样feeding的有害行为 只有在他们的毛虫长到一定阶段的时候这种行为才会消失 注意这种行为是阶段性的

     结论是 用XX方法把这样行为的毛虫一并杀死

     题目要求是weaken这个结论

C选项是很多益虫都会经历这样的毛虫阶段  我们不能仅仅因为毛虫feeding这样一个阶段性暂时性的行为就全部kill 要考虑长远的利益

adolfgao

解释得好清楚呀！谢谢!]

sayysong

不好意思，我想问下为什么B不对？如果不经过那个阶段，这个XX方法就没有效果，不是也是weaken么?

allygmat7

如果不经过这个阶段的话，那个酶就不会产生，也就不会终止荷尔蒙的释放，所以应该应该杀死.

kobemvp

楼上解释没看太懂
该题B选项OG 解释的是本题讨论的是经过这个阶段会产生的影响，而B选项说的是很多pests不经过这个阶段，意思是B是不相关选项吧？

Vickyliu

这道题的关键在问题。问题是复合句，复合句中主句是主要意思，从句次要。
主句意思是：不建议根除昆虫。
大家知道，一句话中名词是一般是客观事物，重点应该是动词，也就是“根除”
所以4个选项只有C选项回答了为什么不建议“根除”。