【请教大牛，想了几个小时都没想明白！！！GWD3-Q32】

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Newspaper editorial:
In an attempt to reduce the crime rate, the governor is getting tough on criminals and making prison conditions harsher.  art of this effort has been to deny inmates the access they formerly had to college-level courses.  However, this action is clearly counter to the governor’s ultimate goal, since after being released form prison, inmates who had taken such courses committed far fewer crimes overall than other inmates.

Which of the following is an assumption on which the argument depends?
A. Not being able to take college-level courses while in prison is unlikely to deter anyone from a crime that he or she might otherwise have committed.
B. Former inmates are no more likely to commit crimes than are members of the general population.
C. The group of inmates who chose to take college-level courses were not already less likely than other inmates to commit crimes after being released.
D. Taking high school level courses in prison has less effect on an inmate’s subsequent behavior than taking college-level courses does.
E. The governor’s ultimate goal actually is to gain popularity by convincing people that something effective is being done about crime.


答案是C。我的疑问是：为什么A不对？
我的解析过程是：
原文：因为上过课的囚犯比没上过课的犯罪率低，所以不让囚犯上课不能减少犯罪率。
原文潜台词：唯有上课才能导致犯罪率低
假设：没有其他因素导致犯罪率低

C说：并不是“选择上课的人本身不容易犯罪”才导致犯罪率低的。没错
但A也说：并不是“囚犯怕不能上课”才导致犯罪率低的。感觉也没错！！！

我想了好久好久好久好久都没想明白，实在郁闷啊~~~ 请问有哪位大牛知道A为什么错吗？

sdcar2010

You should focus on whether A or C has any bearing on the conclusion, not A or C itself makes sense or not.

sdcar2010

Necessary assumption.  Use negation.

If you negate C, you get: The group of inmates who chose to take college-level courses WERE already less likely than other inmates to commit crimes after being released. If so, these group of inmate are GOOD inmates to begin with, with or without the college-level course training. Therefore, the argument that allowing an inmate to take such courses in prison would decrease an inmate's chance of committing crimes after his or her release is false.

Thus, C is the necessary assumption

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Necessary assumption.  Use negation.

If you negate C, you get: The group of inmates who chose to take college-level courses WERE already less likely than other inmates to commit crimes after being released. If so, these group of inmate are GOOD inmates to begin with, with or without the college-level course training. Therefore, the argument that allowing an inmate to take such courses in prison would decrease an inmate's chance of committing crimes after his or her release is false.

Thus, C is the necessary assumption

-- by 会员 sdcar2010 (2012/2/26 1:19:22)

多谢sdcar2010大牛的解释啊！我按照这否定法对A也做了取非，A取非变成：不能上课可能遏制犯罪率，好像也同样削弱了原文“唯有上课才能导致犯罪率低”的结论，因为“怕不能上课”是一种它因，导致原文结论有误，不知道我的推理方式哪里有问题吗？ 再次感谢哈~

sdcar2010

同样削弱了原文 is different from refute a conclusion.

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同样削弱了原文 is different from refute a conclusion.

-- by 会员 sdcar2010 (2012/2/26 11:21:41)

我推敲了sdcar2010的这句话，我理解下来是说：假设取非后要使原文的推理一定不成立，而不是可能不成立？比如A的取非是：“不能上课可能遏制犯罪率”。它因为存在可能的情况，所以未必一定导致原文结论“唯有上课才能导致犯罪率低”不成立，如果A取反变成：“不能上课一定遏制犯罪率”，是不是A就可以成为正确选项了呢？

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sdcar2010大牛，我不知道我这样的理解对吗？

sdcar2010

同样削弱了原文 is different from refute a conclusion.

-- by 会员 sdcar2010 (2012/2/26 11:21:41)

我推敲了sdcar2010的这句话，我理解下来是说：假设取非后要使原文的推理一定不成立，而不是可能不成立？比如A的取非是：“不能上课可能遏制犯罪率”。它因为存在可能的情况，所以未必一定导致原文结论“唯有上课才能导致犯罪率低”不成立，如果A取反变成：“不能上课一定遏制犯罪率”，是不是A就可以成为正确选项了呢？

-- by 会员 popup (2012/2/26 11:30:21)

Yes.

614000

对于我的实力来说，我不能像各位哥哥姐姐这么厉害去分析每句话与原文的逻辑关系，我只能通过北京新东方学到的方法来做出这道题，希望能对楼主有点点帮助。看了N遍题之后我才体会到题目是说一个新的对于囚犯的方法并没有原来的方法好，问假设。首先我能想到老师说的在假设题中首选有否定句的选项，我便排除了D和E，之后由于题目最后的结论是一个比较的句子，则答案中必须是比较的句子因此我就把楼主纠结的A项排除了（希望楼主不要抓狂），最后在B个C中纠结，发现C出现了题目中最重要的college-level courses ，因此我便排除了B。我这样选出了C。希望楼主不要抓狂。也许楼主是早就做出来了是在更深层次的探讨题目，不过希望我能够对楼主的疑惑又一点点帮助

子弹青春

A：no courses    ----  no rate reduce
   Obviously， this does not surely mean courses lead to rate reduce
C：courses make rate reduce
   not other reasons make