求问一道CR

anastasialiu9

Which of the following most logically completes the passage below?

Heavy rains during Centralia's corn planting season prevented some farmers there from planting corn. It is now the planting season for soybeans, another of Centralia's principal crops, and those fields originally intended for corn are dry enough for planting. Nonetheless, even though soybean prices are unusually high at present, the farmers will leave most of these fields empty rather than plant them with soybeans, since________.
Athe extensive rains have led to an increase in the price of corn  
Bsome Centralian farmers anticipate serious financial losses due to the extremely wet spring planting season  
Cchemicals that were used to prepare the fields for corn planting would stunt the growth of soybeans  
Dthe majority of Centralia's corn farmers were able to plant corn as they had intended, despite the wet planting season  
Emany Centralian farmers grow both corn and soybeans  
正解 C
请问A有什么问题，即便选C 的话，化肥会影响soybeans生长，那么不种soybeans只种corns就可以了，怎么会支持原文呢

alzn2765

按照问题类型分类是“solve paradox”类
按照Helr分类是果因推理

题干中有两个逻辑链：
反面逻辑链：
前提（果）：The farmer should plant soybean
结论（因）：Heavy rains during Centralia's corn planting season prevented some farmers there from planting corn+It is now the planting season for soybeans+ those fields originally intended for corn are dry enough for planting+soybean prices are unusually high at present

正面逻辑链：
前提（果）：the farmers will leave most of these fields empty rather than plant them with soybeans
结论（因）：选项

正确选项需要达到两个目的：
1. 削弱反面逻辑结论；
2. 支持正面逻辑结论。

C说那些原本为了种植corn而施在地里的化肥会阻碍soybean的生长

检测：
1. 削弱反面逻辑结论：不管那些“优势”，现在种soybean长不出来，直接否定了“The farmer should plant soybean”
2. 支持正面逻辑结论：既然现在的地已经不适宜种soybean，而种corn的季节又过了，那“leave most of these fields empty rather than plant them with soybeans”也就合情合理了。

所以C是削弱一个增强另一个的正确选项。

A说“the extensive rains have led to an increase in the price of corn”跟农民的选择“leave most of these fields empty rather than plant them with soybeans”有什么直接关系呢？
你犯了三个错误：
1. 题干已经明确指出“Heavy rains during Centralia's corn planting season prevented some farmers there from planting corn. It is now the planting season for soybeans”。这句话什么意思？prevented和now is的意思“就是corn的种植季节已经过去了”，所以根本不存在你说的“不种soybeans只种corns就可以了”的可能性。

2.题干只说了“the farmers will leave most of these fields empty rather than plant them with soybeans”，没说farm will plant corn，这是你自己的“二次推论”。除非你可以证明，“种corn”是“不种soybean”的“唯一必要条件”，也就是“只要农民不种soybean，就必然种corn，绝对不可能有任何其他可能”，你的“二次推论”才能成立。你可以吗？我可以推测农民“不种soybean，空着地”是为了改成足球场？为了停车？为了盖楼？为了盖厕所？为了种大葱大蒜大麻？你如何根据题干信息否定我以上的种种“可能”，从而保证“只要农民不种soybean，就必然种corn”？所以，在无法证明“二次推理”是“唯一必要条件”的前提下（肯定无法证明，不然一道CR题会有论文那么长），任何“二次推理”都是错误的。

3. 讨论范围的界定。整道题讨论的内容是什么？是“种soybean”还是“不种soybean”，这也分别是面反面逻辑链的两个结论。而A讨论的是“种corn的好处”。暂且不考虑种corn的季节已经过去，“种不种corn”跟我要讨论的“种不种soybean”有关系吗？好比我问你“要不要去吃饭？”你回答“要不要去喝酒？”，明显我们讨论的不是同一个问题啊！

jessicamss

alzn2765 发表于 2015-9-27 10:19
按照问题类型分类是“solve paradox”类
按照Helr分类是果因推理

谢谢大神啦！做这题的时候觉得找到削弱在这个土地里中soybeans 的原因就可以了，现在发现了这个solving paradox 类型！！！我一直看的helr的书 没时间看CR Bible，现在感觉helr有点不够用了，因为helr的分类相对宽泛一些？

AnnAys

alzn2765 发表于 2015-9-27 10:19
按照问题类型分类是“solve paradox”类
按照Helr分类是果因推理

此贴已收录至《Alzn大神CD答疑集合》。