It…for…不定式与It…of…不定式

先请看下面两个句子: A.It is difficult for him to do it this way. B.It is wrong of him to do it this way. 在这两个句子中,A 句是It…for…加不定式而B句是It…of…加不定式。两个句子从结构上看差别仅在于A句用for而B句用of。初学者常问,为什么看来相似的两个句子A句中要用for而B句中则用of? 在A句中for him to do it this way是一个不定式复合结构。