对CR快速读问题的菜鸟小结--根据Lawyer分类

shaoheng1120

C is a sufficient assumption while D is a necessary assumption. Depending on the question stem, either one could be the correct answer to an assumption question. C is not a necessary assumption while D is not a sufficient assumption. That is my point of highlighting the importance of knowing whether the question asks for a sufficient assumption or a necessary one.

Not all assumptions are necessary.

Not all assumptions are sufficient.

-- by 会员 sdcar2010 (2012/1/3 12:23:21)

斑竹：我理解是不是C由前提推出来，所以是充分假设。
         而其他的是和前提并列关系，就是必要假设。
请赐教！

sdcar2010

I am not 斑竹.

There are three statements in the passage:

Statement A. Statement B. Therefore, Statement C.

If a Statement D says "If A, then C", then D is the sufficient assumption.

Necessary assumption is a statement without which, the conclusion--statement C--cannot hold.

C is a sufficient assumption while D is a necessary assumption. Depending on the question stem, either one could be the correct answer to an assumption question. C is not a necessary assumption while D is not a sufficient assumption. That is my point of highlighting the importance of knowing whether the question asks for a sufficient assumption or a necessary one.

Not all assumptions are necessary.

Not all assumptions are sufficient.

-- by 会员 sdcar2010 (2012/1/3 12:23:21)

斑竹：我理解是不是C由前提推出来，所以是充分假设。
         而其他的是和前提并列关系，就是必要假设。
请赐教！

-- by 会员 shaoheng1120 (2012/1/4 12:06:54)

sdcar2010

A better question to differentiate sufficient assumption and necessary assumtion is the following:

SDCAR gets A’s in English. Therefore, SDCAR must be intelligent.

The author’s conclusion would be properly drawn if which one of the following was true?

a) SDCAR gets good grades in all of his math classes.
b) All Americans named SDCAR are smart.
c) SDCAR wouldn’t get A's in English if he wasn’t smart.
d) Some people who get A’s in English are smart.
e) Everyone who gets an A in Math is smart.

sdcar2010

In the second version, C) is sufficient but not necessary; D) is necessary but not sufficient.