Og CR 631求助

IWANT750

Scientists have modified feed corn genetically, increasing its resistance to insect pests. Farmers who tried out the genetically modified corn last season applied less insecticide to their corn fields 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 modified seed would be unlikely to increase profits.
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 modification 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 modified corn last season applied more insecticide than was actually necessary
(E) Whether, for most farmers who plant feed corn, it is their most profitable crop

看了解释也想不通为什么选D
题干里不是已经说了modified corn比ordinary corn用更少的杀虫剂了吗，那为什么D选项又在对比modified corn需要的杀虫剂量和实际必要的杀虫剂量？题干中已经解释过了啊。选项中的actually necessary不就是指的ordinary corn需要的杀虫剂计量吗？

Fiona09

题目说的是：一种转基因玉米，可以抵抗虫害，减少使用杀虫剂。但是价格要比普通的贵。因为减少用杀虫剂省下来的钱和买种子多花的钱差不多，而产量也大致一样，所以这种转基因的玉米不能带来更高的利润。

问的是：使用基因改造的种子是否可以增加利润呢？

简化下题干信息——基因改良种子可以节省杀虫剂的费用，但是这个费用必须要与为这个种子多花费的钱相比较，是否有利可图？

D项说的是：是否在去年用在基因改造玉米上的杀虫剂比实际需要的多？

如果杀虫剂的用量可以减少，这样利润就会变高——削弱结论
如果杀虫剂用量无法减少——就support了结论