论坛的大神在哪里？？？ OG16 最后一题 逆否命题为什么是削弱不是加强？

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124. It is widely assumed that people need to engage in intellectual activities such as
solving crossword puzzles or mathematics problems in order to maintain mental
sharpness as they age. In fact, however, simply talking to other people—that is,
participating in social interaction, which engages many mental and perceptual
skills—suffices. Evidence to this effect comes from a study showing that the more
social contact people report, the better their mental skills.
Which of the following, if true, most seriously weakens the force of the evidence
cited?
(A) As people grow older, they are often advised to keep exercising their
physical and mental capacities in order to maintain or improve them.
(B) Many medical conditions and treatments that adversely affect a person’s
mental sharpness also tend to increase that person’s social isolation.
(C) Many people are proficient both in social interactions and in solving
mathematical problems.
(D) The study did not itself collect data but analyzed data bearing on the
issue from prior studies.
(E) The tasks evaluating mental sharpness for which data were compiled by
the study were more akin to mathematics problems than to conversation.
正确答案是B 看了别人的讨论说是属于因果倒置型削弱。不明白的是：B不就是逆否命题吗？逆否命题不就等于原命题吗？那不就是加强原文了吗？我哪里想错了？

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有人能帮忙解答下吗？？

ET游戏狂

快来人看看…

ET游戏狂

有没有人解答下 大神快来帮忙看看啊！

ET游戏狂

来人啊

哑舍

逆否命题是针对的相关关系，这里是因果关系