og12-69

swlfxer

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

答案D把原文的Farmers who tried out the genetically modifi ed corn last season applied less insecticide  质疑了下，既然是原文都说了，再去质疑对吧？

一般evaluation结论的题目可以这样吗？

大部分是不是应该找到结论和前提之间的空白来质疑呢？

detectiveyangs

此题的论证结构
大前提：利润=价格X产量-杀虫剂成本-种子成本，
小前提一：使用基因饲料玉米会增加种子成本，但减少杀虫剂成本，产量不变。
小前提二：种子成本增加多于杀虫剂成本减少
结论：使用基因饲料玉米不会增加利润。
这个论证唯一没有交代的是价格，但选项中没有价格。所以没有所谓的空白，如果三个前提都为真，则结论为真，质疑任何一个前提都可以影响结论的真实性。
答案D质疑了小前提二，有效。

piacia

我觉得 虽然题目已经说了 less  但是还有可能需要用的杀虫剂 比less还要少

小月潇湘

同意
D的意思是，是否用转基因的farmers用杀虫剂用多了。
也就是比题干中的less还要less

zhaoyiqing

大家好像想复杂了，题目中是说了转基因玉米的农药用量相对少。不过这并不影响答案D中提出的假定。

答案D中，农药的用量能否进一步减少显然直接关系到转基因玉米的生产成本，当然就是衡量原题中论断是否成立的一个条件。

再看看其他选项，D应该是最佳选择。

templars

如果是的话也不能证明结论啊，即使转基因种子在种植时不用杀虫剂，其种子的价钱还是有可能比普通种子和杀虫剂高啊，这个是不确定因素啊？利润还是不确定啊？！~

banglixing

我也做错了。。看了后自己是这样想的，主要条件：改基因谷子用的杀虫剂少，但是价钱贵。 普通谷子便宜，杀虫剂多了点。 附加条件：杀虫剂其实很便宜 。两种谷子产量相近。

这样看下来，似乎所有不利的条件都在改基因谷物上。因此 唯一有可能扭转的条件就是，是不是在这个实验里改基因谷子在种时，农药用了不必要的量。 如果过量了。那可能改基因谷子实际上花不了这么多钱。

templars

同问啊，今天做到这题也没看懂答案
题目不是已经说了，
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.
为什么答案还有说花更多的钱在杀虫剂上面啊？？
牛牛们解释一下啊