请教一道逻辑GWD6-21 万分感谢！

Scientists have made genetic modifications to cotton to increase its resistance to insect pests.  According to farmers’ report, the amount of insecticide needed per acre to control insect pests was only slightly lower for those who tried the modified seed than for those who did not.  Therefore, since the modified seed costs more than ordinary seed without producing yields of higher market value, switching to the modified seed would be unlikely to benefit most cotton farmers economically.

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

A.   Whether farmers who tried the modified cotton seed had ever tried growing other crops from genetically modified seed

B.   Whether the insecticides typically used on ordinary cotton tend to be more expensive than insecticides typically used on other crops

C.   Whether for most farmers who grow cotton it is their primary crop

D.  Whether the farmers who have tried the modified seed planted as many acres of cotton, on average, as farmers using the ordinary seed did

E.   Whether most of the farmers who tried the modified seed did so because they had previously had to use exceptionally large quantities of insecticide

答案是D  想不通  请大家帮帮忙

其实讲来讲去，最后得出的结论就是：让农民去种改良过的种子是不经经济的，也就是农民不会用改良过的种子，还是用传统的种子。

可是题干已经说明是每英亩地的杀虫剂使用量之间的比较   D项说总的公亩数是什么意思呢？

http://forum.chasedream.com/dispbbs.asp?boardid=24&replyid=524693&id=58110&page=1&skin=0&Star=4

这个帖子颇有争议 不过我觉得还是D比较靠铺 因为文中according to farmer's report后面 对使用改良种子的人和没使用改良种子的人进行比较后得出改良种子的农药只比没改良的slightly lower ，而D是比较的基础。

这只是我的想法 otd

题目中说农民用改良后种子的使用的杀虫剂并不比使用没改良的低多少

d选项说是否使用改良后种子的农民耕作cotton的平均面积与使用普通种子的差不多。

如果使用改良cotton种子的农民一共耕作了很大面积的土地，但是只有一小部分是cotton，所以即时这一部分完全不用杀虫剂，总体上杀虫剂量也只比使用普通种子的农民低一点。反向证明D选项正确

用杀虫剂控制害虫     用基因改良控制害虫

题目是对这两者在控制害虫量上的比较.----杀虫剂只比基因改良低一点,推出结论.

问题是要求一个推出该结论的前提的补充,即一个必要条件.个人理解为加强比较与结论的关系.所以,使比较更有正式性就必须保证合理性.

所以,量的比较应该在同等参照量的前提下.

switching to the modified seed would be unlikely to benefit most cotton farmers economically，最后这句是说的钱，这个题以前有过争议，lawyer大牛说是b，我认为也应该是b的，只有b在 说钱的事，意思就是即时the amount of insecticide needed per acre to control insect pests was only slightly lower for those who tried the modified seed than for those who did not，但如果那个insecticide很贵的话省一点量也能省很多钱了吧

感觉这题没什么意思，太纠结

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