It is diffcult for him to do it it是不是形式主语 is diffcult是不是谓语 for him是不是状语

问题描述:

It is diffcult for him to do it it是不是形式主语 is diffcult是不是谓语 for him是不是状语

这是一个主语从句,前面的it是形式主语,真正的主语是to do it,for him是定语,is difficult是系表结构.