OG12 CR69

tonyadid

69.     Scientists have modi?ed feed corn genetically, increasing its resistance to insect pests. Farmers who tried out the genetically modi?ed corn last season applied less insecticide to their corn ?elds and still got yields comparable to those  they would have gotten  with ordinary corn. Ordinary corn seed, however, costs less,

and what these farmers saved on insecticide rarely exceeded their extra costs for seed. Therefore,  for most feed-corn farmers, switching to genetically modi?ed seed would be unlikely to increase pro?ts.



Which of the following would it be most useful to know in order  to evaluate the argument?



(A)       Whether there are insect pests that sometimes reduce  feed-corn yields, but against which commonly used insecticides and the genetic modi?cation are equally ineffective

(B)      Whether the price that farmers receive for feed corn has remained  steady over the past few years

(C)      Whether the insecticides typically used  on feed corn tend to be more expensive  than insecticides typically used on other crops

(D)      Whether most of the farmers who tried the genetically modi?ed corn last season applied more insecticide than was actually necessary

(E)     Whether, for most farmers who plant feed corn, it is their most pro?table crop


答案是D，我选B。feed corn和genetically modi?ed corn价钱应该不一样啊，为啥OG答案说Whether prices of feed corn go up or down a?ects the comparison groups equally.而且为啥选D我也不理解，希望谁能给我解释一下。万分感谢

findjuhl

题目说：农民去年尝试了改良基因的玉米，他们在农药上节省下来的钱和买这种种子多花的钱差不多，所以说，换改良玉米给农民不会增加利润。

问以下哪点对判断结论最有用

d: 农民是否在改良基因的玉米上面多用了农药， 如果是，那事实上他们以后可以少用农药，那么就可以节省更多的钱，题目中的结论就不成立

b。玉米前几年的价格是否稳定  这个和题目不相关，因为题目结论建立的基础在于农药花的钱和种子花的钱作比较，改良基因玉米和普通玉米作比较，不涉及到玉米价格

tonyadid

解释得很清楚。。明白了，非常感谢哦

callmesoli

我选的是A，A的意思是有种害虫会使玉米产量减少，为了杀死害虫，所使用的杀虫剂和改良玉米作用就会相互抵消。
OG解释里面说，it does not matter to the argument whether there are pests against which pesticides and genetic resistance are equally ineffective, because that is compatible with there being pests against which they are not equally effective.
我还是不明为哈A是错的，OG解释的后半句because 。。。。看不太懂。请大家指教。谢谢。

Jackjokes

我是真心有个人回复我一下这个问题啊， 我对A 是这么理解的，有一种害虫（有些时候会减少f-c的产量），但是普通杀虫剂和Genetic modification 是否对抗它是同样有效的？
回答是：就是同样有效的，既然同样邮箱有效就对原文结论起到支持作用。
回头否：就是不是同样有效的。 可是，“不是同样有效“ 的意思是说 要不C的效果大于G， 要不G的效果大于C。得不是任何结论

psycheps

A: Whether there are insect pests that sometimes reduce feed-corn yields, but against which commonly used
insecticides and the genetic modifi cation are equally ineffective
是否存在一些虫子有时候是会减少谷物产量的，而且能抵抗普通常用的杀虫剂和那些基因修饰谷物（即基因修饰谷物也对害虫不起作用）？

这是我从另一个网上看到的人家的解释。

如果有这样的虫子，作用在转基因种子和正常种子上是一样的，也就是说，两种种子产量还是一样的。于是对于转基因玉米是否会赢利多余普通玉米这个问题上是无关的。