GWD的一道CR，关于可抗虫的棉花

JoshwuS

Plantings of cotton bioengineered to produce its own insecticide against bollworms, a major cause of crop failure, sustained little bollworm damage until this year.  This year the plantings are being seriously damaged by bollworms.  Bollworms, however, are not necessarily developing resistance to the cotton's insecticide.  Bollworms breed on corn, and last year more corn than usual was planted throughout cotton-growing regions.  So it is likely that the cotton is simply being overwhelmed by corn-bred bollworms.

In evaluating the argument, which of the following would it be most useful to establish?

	Whether corn could be bioengineered to produce the insecticide
	Whether plantings of cotton that does not produce the insecticide are suffering unusually extensive damage from bollworms this year
	Whether other crops that have been bioengineered to produce their own insecticide successfully resist the pests against which the insecticide was to protect them
	Whether plantings of bioengineered cotton are frequently damaged by insect pests other than bollworms
	Whether there are insecticides that can be used against bollworms that have developed resistance to the insecticide produced by the bioengineered cotton

感觉B讲的是不能产生杀虫剂的COTTON，所以就排除了，想不明白为什么答案是B

brunhildS

我的感觉是如果cotton that does not produce the insecticide能够抵挡住害虫的侵害的话，原来的结论就被削弱了，不会overwhelmed by corn-bred bollworms.
如果不能抵挡住的话，那些产生杀虫剂的棉花已经完蛋了，这些不能产生的也完蛋的话，那就都overwhelmed啦

rudder86

文中说Bollworms影响作物收成，结论说这一年cotton收成不好是因为收到玉米产生的Bollworms的影响。这两个概念是独立的，怎么样能使得从前面一个条件的角度看这个结论更可信呢？
看这5个选项
ACDE都是无关
再看B，B说不会产生杀虫剂的cotton是否会被这种虫子影响
如果知道普通cotton也会被这种虫子影响，那就增加了产生抗生素的cotton会被其他作物（例如玉米）产生的虫子影响这一结论的可信度
所以选B
希望对你有帮助～

xiruihuang

我觉得这题没有答案 是个滥题。

题目想evaluate的是植物自己产生的杀虫剂的失效（抗药性）导致了被植物被吃，还是只因为害虫数量太大压倒植物。

ETS最喜欢把“去掉一种条件状况下的结果blabla作为正确答案”

但是这题很特殊，对于不产生杀虫剂的普通植物，如果也被害虫吃掉，显然与杀虫剂无关，原因可能是被害虫数量压倒，但不确定。
如果没有被害虫吃掉，原因必然是不确定的。
显然无论如何， 这个评估都无法对提干的逻辑应对。

xiruihuang

补充一句如果选B， 其实有一个附加的assumption：  自己产生杀虫剂的植物相比普通植物有可能因为害虫的抗药性反而更加容易被吃掉(杀虫剂好象“反作用”)。