[求助]OG-48，谢谢！

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.

我已明白Ｄ是ASSUMPTION，但请问Ａ和Ｃ有什么问题？

A. High immune-system activity protects against mental illness better than normal
immune-system activity does.

immune-system 高，mental health高

A取非：immune-system 高，mental health低，weaken结论

C. People with high immune-system activity cannot develop mental illness.

C取非：immune-system 高，mental illness高，weaken结论

请大牛帮忙！谢谢！

D排除了因果倒置的可能，所以是题目结论需要依赖的一个假设。

但题目的结论并不需要依赖于A和C的正确。

我觉得无关。A,C混淆了题干里的充分必要条件

"A,C混淆了题干里的充分必要条件"

请问是怎么混淆充分必要条件的咧，我看ＯＧ都看了三遍了，ＯＧ还是象天书一样，看不懂？

Ａ／Ｃ中immune-system －必要条件，mental illness－充分条件，是吗？

各位大牛，请帮忙，实在是不明白，Ａ／Ｃ到底是那里错了？谢谢！