It is diffcult for him to do it 谓语是is diffcult吗 那for只是介词吗

问题描述:

It is diffcult for him to do it 谓语是is diffcult吗 那for只是介词吗

It(形式主语) is (谓语) diffcult(表语,宾语) for him to do it (真正的主语)。

to do it 是整个句子的真正主语, 它被句首的It代替了, 句首的It是个形式主语,is difficult 是句子的谓语, 属于系表结构。,for是个介词,

谓语动词是系动词is for在这里是介词

is 是谓语

It 是形式主语

谓语?应该是do it的do
for应该是介词

本句子是遵循了英语中的常用处理方法,避免头重脚轻。it 做形式主语,to do it 做真正的主语,谓语是is
如果要还原句子本来面目应该是to do it for him is diffcult,这样本来是没问题的,但是这样的话句子主语太长,谓语太短,所以就成加来it来改善
很多时候句子都是这种,它可以记忆为: it is +形容词+for sb to do sth

It is diffcult for him to do it.
此句完全正确,你说得也非常对!谓语是is diffcult,是系表结构做谓语;for是介词;

形式主语it
真正主语to do it
系动词is
表语difficult
状语for him