一道假设题

M:It is almost impossible to fina a person between the ages of 85 and 90 who primarily uses the left hand.

Q:Seventy to ninety years ago,however,children were punished for using their left hands to eat or to write and were forced to use their right hands.

Q's reponse serves to counter any use by M of the evidence about 85 to 90 year olds in support of which one of the following hyperothese?

A Being born righthanded confers a survival advantage.]

B Social attitudes toward handedness differ at different times.

C Forcing a person to switch from a preferred hand is harmless.

D Handedness is a product of both genetic predisposition and social pressures.

E Physical habits learned in school often persist in old age.

答案为什么不是Ｅ而是Ａ，请高手指教！

The question is asking that Q's answering counters what M's conclusion.

The Q's answering mainly explains why the rate of using left hand in 85 to 90 is so low. The major reason is that the social attitudes to left hand are changing.

The implicit conclusion of A is that the people who don't use left hand can live up 85 to 90 years old.

从Q的回答能推出它支持A这个假设？

M中的primarily 是翻译成最初，还是主要？

1。primarily: 主要地

2。问题：M要用上述证据得出以下结论（假设），Q的回答反对M得出下面结论

3. Q说80-90岁的人几乎没人主要用左手。原因是天生用右手好，易于生存。

    M提出不同看法：那个年代小孩不能用左手，否则会被罚（A）