请教:OG-48题,死活不明白

就是不明白,谢谢各位指点.

-48. A researcher discovered that people who have low levels of immune-system activity tend
to score much lower on tests of mental health than do people with normal or high
immune-system activity. The researcher concluded from this experiment that the immune
system protects against mental illness as well as against physical disease.
The researcher’s conclusion depends on which of the following assumptions?
A. High immune-system activity protects against mental illness better than normal
immune-system activity does.
B. Mental illness is similar to physical disease in its effects on body systems.
C. People with high immune-system activity cannot develop mental illness.
D. Mental illness does not cause people’s immune-system activity to decrease.
E. Psychological treatment of mental illness is not as effective as is medical treatment.

答案:The researcher concludes from the association of low immune-system activity with low
mental-health sores that, in effect, immune system activity can inhibit mental illness. If,
contrary to D, mental illness can depress immune-system activity, the association mentioned
does not support the researcher’s conclusion. So D must be assumed. Normal
immune-system activity could protect against mental illness without high-immune system
activity offering increased protection or prevention, contrary to what A and C state, so neither
of A and C is assumed. The conclusion does not depend on there being a similarity between
mental and physical illness or a difference in treatments, so B and E are not assumed.

一点看法，供参考

结论：“免疫力”是因，“没有精神疾病”是果

A. High immune-system activity protects against mental illness better than normal immune-system activity does. —>跟原文“中等的免疫也可以protect”反了

B. Mental illness is similar to physical disease in its effects on body systems. --无关

C. People with high immune-system activity cannot develop mental illness. —>跟原文反了

D. Mental illness does not cause people’s immune-system activity to decrease. —>取消倒因果（即不是精神疾病引起的免疫系统活动下降），如果是由精神疾病引起的免疫系统活动下降，则作者结论：免疫功能保护精神 被削弱了

E. Psychological treatment of mental illness is not as effective as is medical treatment. —>与用什么方法治疗更有效无关

看到楼主的"死活不明白",总算体会到了"同是天涯沦落人，相逢何必曾相识"的意境.因为我刚上来准备把这题贴出来呢.

我一开始选B,其实仔细在看看这题,通篇根本没提到immune-system与physical disease的关系,只是一直在说immune-system与mental health,mental illness的关系,只是结论的最后一个词提到了physical disease,而我自己当时觉得immune-system不就是来protect against physical disease的吗?无意中加上了自己的assumption.所以总也想不明白.

现在刚刚明白了......

To楼主MM：

简单来说：要得到结论“是A保护B”（这是一个因果关系），我们是不是先应该假设“不是B影响了A”呢？也就是要排除因果颠倒的关系。

看回原文和选项C：

先不看它们具体是什么作用的，先提取其中的因果关键词：Mental illness和immune system。原文中immune system是因，mental illness是果；选项C改为：mental illness是因，immune system是果（其中用not连接，即不是mental illness导致的immune system）

说得太唐僧，MM明白就好了。

以下是引用ring_cheng在2005-6-24 14:18:00的发言：

To楼主MM：

简单来说：要得到结论“是A保护B”（这是一个因果关系），我们是不是先应该假设“不是B影响了A”呢？也就是要排除因果颠倒的关系。

看回原文和选项C：

先不看它们具体是什么作用的，先提取其中的因果关键词：Mental illness和immune system。原文中immune system是因，mental illness是果；选项C改为：mental illness是因，immune system是果（其中用not连接，即不是mental illness导致的immune system）

说得太唐僧，MM明白就好了。

to ring_cheng:

觉得你讲的很有道理，那是不是 ‘排除因果颠倒的关系’这种方法是一类题的解决方法那》？若有，麻烦再给列几个。多谢

实际上，我对此题的思考是这样的：

前提：学者发现： low levels of immune-system activity 趋向lower on tests of mental health   是伴随的两现象，无明确的因果关系。

结论：the immune
system protects against mental illness as well as against physical disease  这里就有了因果关系了。

对于假设题，排除他因和架桥嘛！

D 恰恰是个排除一个他因。即，不是mental illness 导致 immune
system （不是 果 导致了 因。）

。。。。

不知道大家能不能看明白我写的。。

继续讨论

to easysummer：是的，要建立正常的因果关系，排除“倒因果关系”是其中的假设之一。OG137（睡势和婚姻关系）以及费费说的“人吃动物”题也是。OG上此类的例子很少。

我感觉一般在文章中出现A tend to B，结论就说A导致B时，一般用倒因果比较好。其它的削弱方式lawyer牛牛已经在精华贴中有过很详细的说明，请看看。

多谢ring_cheng

ASSUMPTION 取非即为 WEAKEN， 那么这一题答案是 NOT + WEAKEN ,所以 WEAKEN 取非 也是 ASSUMPTION了？？

NN来解惑呀！。。

天哪！我做其它逻辑题也没这样啊！

为什么我越看越糊涂呢，我怎么就觉得第五楼“选项C改为：mental illness是因，immune system是果”是反着的哪？！

彻底晕了！

不知道哪位能把这个题翻译出来？那样能不能易于理解？