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标题: 菜鸟再问一个逻辑 [打印本页]

作者: kingsoft 时间: 2004-5-15 00:02
标题: 菜鸟再问一个逻辑

often patients with ankle fractures that are stable, and thus do not require surgery, are given follow-up X-rays because their orthopedists are concerned about possibly having misjudged the stablilty of the fracture. When a number of follow-up X-rays were reviewed, however, all the fractures that had initially been judged stable were found to have healed correctly. Therefore, it is a waste of money to order follow-up x-rays of ankle fracture initially judged stable

support

A: doctors who are general practitioners rather than orthpedists are less likely than orthpedists to judge the stability of an ankle fracture correctly

B: many ankle injuries for which an initial x-rays is ordered are revealed by the x-ray not to invlove any fracture of the ankle.

C: X-rays of patients of many different orthopedists working in several hospitals are reviewed

D: the healing of ankle fractures that have been surgically reqired is always checked by means of a follow-up x-ray

E: orthopedists routinely order follow-up x-rays for fractures of bone other than ankle bones

这个题目其实很简单，但我水平太菜，看到答案了，只是模糊的觉得其对，但是似乎还是没理清其中逻辑关系，请NN确认一下答案，并指点一下理由，谢谢谢谢！！！！

作者: babypace 时间: 2004-5-15 00:27

I choose E.

作者: mariezhu 时间: 2004-5-15 11:51

看看睡熊GG的这个总结对你会不会有帮助?

"可以加强的形式有：

（1）A有效并保持；（2）B可能；（3）~A -> ~B (否命题型加强)；（4）A -> B （原文改写型加强）"

此题的加强方式正是(1)

作者: dreadpower 时间: 2004-5-15 21:48
睡熊的总结原稿在那里？？？

作者: mariezhu 时间: 2004-5-15 22:16
我从睡熊答疑的一个帖子上扒下来的,存在自己的电脑里,今早找出来的,原话是:

判断的原则是：对于A -> B,

可以加强的形式有：

（1）A有效并保持；（2）B可能；（3）~A -> ~B (否命题型加强)；（4）A -> B （原文改写型加强）

可以削弱的形式有：

（1）A无效或已不保持；（2）B不可能；（3）B -> A (因果关系颠倒型削弱)；（4）A -> ~B (否定结论型削弱)

其它形式都不构成加强或削弱。对照你找到的所有例子，看看是不是已经非常清楚了

觉得很简明而且有启发性.至于睡熊有没有进行其它系统的总结,我就不知道了.

作者: dreadpower 时间: 2004-5-16 20:49

恩，好总结！！

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