请教一道有争议的逻辑题。（自己对这道题已有一点想法）

molynca0717

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 farms 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.

做PREP时候系统给的答案是B，所以我不怀疑其正确性。
以下是我的思路请大家帮看一下对不对：
【题干】转基因种子有抗虫性，但是实践发现转基因棉花种子所用杀虫剂只比普通棉花种子少一点，而前者的价格要比后者高同时产量不变。那么要不要使用这种转基因种子呢？
【B】考察是否给棉花种子用的杀虫剂要比给其他农作物用的贵？假设很贵，那么即使只是少用一点农药，也能省不少钱。（对）
【E】考察是否大多数尝试使用转基因种子的人以前使用了大量的杀虫剂？假设大量使用，但由于不知道杀虫剂的价格，所以无法判断。（错）

690387114

很少有人能注意到这是个experiment， According to farmers’ report, 各项对比指标的结论是由farmer's report得出的。
D质疑了样本代表性，两组对比实验的条件要相同。有可能实验转基因种子的这些农民，每亩种的cotton特别多，导致每亩需要的杀虫剂多。

国腾一哥

北冰洋不是洋 发表于 2016-10-4 01:13
应该选D

B是比较的是杀虫剂用在ordinary的crops上和杀虫剂用在other crops上的比较 但是这里没有other  ...

你自己说的服自己吗？杀虫剂成本当然和使用量成正比，不然这题还有法做吗？

percentile99

pansimply 发表于 2017-3-29 21:54
http://www.beatthegmat.com/genetic-modifications-to-cotton-t31971.html

I think D is a trap. In the  ...

看了你这个解释后，这题的争议可以终结了

zixuan1017

感谢分享！               

kluivert

slight lower or higher 意思是几乎可以忽略不计..about the same ...所以b一定错
b比较的是cotton 和 其他作物的价格区别..更没意思
而E的意思是农民习惯大量用杀虫剂，即便是在用了新种子，这个当然浪费了！假如新种子本来需要一斤杀虫剂，但农民还是用以前的普通种子用量-10斤，那就造就了浪费了大量的钱

pansimply

http://www.beatthegmat.com/genetic-modifications-to-cotton-t31971.html

I think D is a trap. In the argument, we are told that the amount of insecticide needed per acre to control insect pests was only slightly lower so it doesn't matter how many acreage of cotton each type has, what matters is the comparative cost of the insecticide.

IMO In evaluate the argument questions look for a answer choice which when answered positively strengthens/weakens the conclusion and when answered negatively does the vice versa.

Choice A,B,C are unrleated to the argument(conclsuion).

Choice D looks tempting but if u answer yes and no it does not affect the conclusion both ways.


Choice E does this.

The conclusion is 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.

If the answer to the question for choice E is yes then it means the farmers switched to the modified seeds only bevcause they had to use large quantities of insecticides that would have costed them more(if not ther is no reason to switch)

If the answer to the question for choice E is no then it means the farmers had no good reason to switch and the the argument that modified seeds are not economically benefiicial to the farmers stands.

Hope this helps!

Regards,
CR

zcy1233

北冰洋不是洋 发表于 2016-10-4 01:13
应该选D

B是比较的是杀虫剂用在ordinary的crops上和杀虫剂用在other crops上的比较 但是这里没有other  ...

也就是说，比较insecticide时排除了面积因素，但是比较yields/market value时，没考虑面积。是这样理解吗？

胡茗译

这题我看到各种答案的时候也是很闹心啊，明明是E嘛。

B选项：argument只比较转基因的和种子和普通（ordinary）种子的区别，根本没有other crops的事儿，再典型不过的irrelevant，怎么可能是正确选项？
D选项：文中明确的说了是per acre的费用slightly lower，不过度脑补的话economically省钱跟种植面积从文中信息是无从推断的。
E选项：只要读懂题的话其实就很简单了啊，都是per acre的cost，但是在转基因作物的田地里，农民用量远大于实际需要，也就是说其实转基因棉花每亩所需要的杀虫剂要远远少于普通棉花，只需要一层推导，非常直接，完美选项

fzjj

这道题我得到经验是不能提前想答案，一看到benifit 忍不住想价格 利润 马上就错选往上靠的B了