Nothing is so easy as parents to raise their expectations of their children too high.A. o

Nothing is so easy as parents to raise their expectations of their children too high.
A. of
B. for
C. by
D. to

A. of(答案→)B. forC. byD. to解析：考查介词用法。当介词前面的形容词是对指人的主语的性格特征进行说明的时候，使用介词of;如It is kond of you to do so.当形容词不是对句子主语的性格特征进行说明的时候，就使用for；如It is difficult for him to read that book。本句中的easy并不是对人的性格特征进行说明的形容词，故使用for。故B正确。

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