本来也选了B，（因为受OG12做过类似内容的题的影响），但看了如上讨论，觉得是D。这里的B为什么不对？ 因为B用的是一个一般性的描述，来描述农民种田用杀虫剂的方式。（ typically use agricultural pesticides in larger amounts than is necessary to prevent crop damage），而没有说是对原来的普通种子呢，还是对现在的新型种子。所以就如cherry同学所说，这是农民的一种手法，如果是保守型，喜欢用大剂量，那无论用啥种子都是大剂量。
OG那道题相反，选项中说的是，农民对新型种子所用的剂量是不是larger than necessary 了，这直接影响了两个被比较方法之一，而不是同时影响。
这是OG12 的69题
69. Scientists have modifi ed feed corn genetically, increasing its resistance to insect pests. Farmers who tried out the genetically modifi ed corn last season applied less insecticide to their corn fi 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 modifi ed seed would be unlikely to increase profi 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 modifi 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 modifi ed corn last season applied more insecticide than was actually necessary (E) Whether, for most farmers who plant feed corn, it is their most profi table crop Argument Evaluation Situation Farmers who grew feed corn genetically engineered to be pest resistant got yields comparable to those of farmers growing ordinary feed corn, but did so while using less pesticide. Since the amount saved on pesticide was rarely in excess of the extra costs for the genetically modifi ed corn, most farmers will probably not increase profi ts by choosing the genetically engineered variety. Reasoning Which would be most useful to know in evaluating the argument? To answer a question such as this, one should look for information that would strengthen or weaken the argument. If one had information that the farmers growing the genetically modifi ed corn could have increased their yields last year at lower cost, this would be helpful in evaluating the argument, because this would show that the argument is weak. A It does not matter to the argument whether there are pests against which pesticides and genetic resistance are equally ineff ective, because that is compatible with there being pests against which they are not equally eff ective. B Whether prices of feed corn go up or down aff ects the comparison groups equally. C Th e relative cost of insecticides for other crops has no bearing on the argument because the argument is concerned with only feed corn. D Correct. Th is option provides the information that it would be most useful to know in evaluating the argument. It shows that farmers growing genetically modifi ed corn last year could have attained higher profi ts than they in fact did. E Th e argument concerns only the relative profi tability of growing one variety of feed corn versus another. Th e correct answer is D.
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发表于 2009-7-13 19:44:00
