【HELP】~~求助GWD转基因棉花&Bollworm题一道~~

h3701485

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 be most useful to establish?

A.Whether corn could be bioengineered to produce the insecticide

B.Whether plantings of cotton that does not produce the insecticide are suffering unusually extensive damage from bollworms this year

C.Whether other crops that have been bioengineered to produce their own insecticide successfully resist the pests against which the insecticide was to protect them

D.Whether plantings of bioengineered cotton are frequently damaged by insect pests other than bollworms

E.Whether there are insecticides that can be used against bollworms that have developed resistance to the insecticide produced by the bioengineered cotton

答案为神马选B呢......大家给我开导开导吧。。。。题一做多就发懵。。。。。HELP~~THX a lot!!!!

cycyang

从题干：过去种植一种转基因棉花（能够自身产生威胁其生长的虫类杀虫剂）的种植能够有效控制虫类对棉花生长的破获，而今年，这种虫类破坏严重，尽管事实上虫类不能抵抗这种杀虫剂的功效。

之后得出结论：这种虫子以棉花为食，同时去年在产棉区种植的棉花比以往都多，所以很可能所种棉花仅仅是被这种虫类侵袭。

B.Whether plantings of cotton that does not produce the insecticide are suffering unusually extensive damage from bollworms this year
非转基因棉花（不产生杀虫剂）的种植今年是否也受到了这种虫害影响。如果是，则支持了结论；如果不是，则削弱了结论，因为这就说明很有可能存在其他破坏棉花生长的因素。

holdonzz

我是这样理解的：
题干： 含抗虫功能的棉花（C1)的抗虫效果一直不错。但是直到今年，C1被虫子严重侵害了，却不是因为虫子产生了针对其的耐药性而至。（注意，这之前的事实交待都是针对于C1的，plantings +of结构; the plantings均特指C1）然后文章又说虫子以玉米为食，且在去年，棉花种植区域里种下了更多的玉米。结论：棉花很容易被这种以玉米为食的虫子攻克。

其实，题干的后两行的棉花均是泛指在种植区域里棉花的概念。而前面交待的事实却均是针对抗虫功能的C1所说。因此结论变相扩大了范围。
所以要想使这个扩大范围的结论成立，必须要满足下面两个情况的任意一个：
1.今年种植区域里的棉花全部种的都是含抗虫基因的。（这个情况答案里没有，仅是我认为的另一种让结论成立的可能）
2.不光抗虫棉花被严重侵害，区域里的不含抗虫基因的棉花一样也遭到严重破坏。（这恰好是答案B的意思）

希望这个解释能对你有帮助~

ran2010zx

经典题~
原文说的是平常是很有效的
但这次无效了——并归结于是因为虫子太多了——那么其实还是有效地
那么如果没有抗虫基因的收到了更加大的危害——说明确实转基因的还是有效的——只是确实虫子太多了

gmat小菜鸟

楼上正解

angelcity

看到LS这句的时候终于让混乱的思路清楚了:"题干的后两行的棉花均是泛指在种植区域里棉花的概念。而前面交待的事实却均是针对抗虫功能的C1所说。因此结论变相扩大了范围"
可是，俺 想知道，如何在高度紧张还超级短的时间里把这些概念都一一看清并保持清醒啊?额的个神~

carilyn1031

题干里不是还有corn--玉米的事了么？为何大家把cotton和corn都称作棉花？