关于一个动词短语的用法请问what we should do is to talk about.what we should do is talking about...这两句中talk about是动词短语,但是用在is后面时,应该这么用呢?类似的一句还有:this subject is mainly to talk about....请问这种表述是对的吗?还是this subject mainly talk about...或者是this subject is mainly talk about?:)

问题描述:

关于一个动词短语的用法
请问what we should do is to talk about.
what we should do is talking about...这两句中talk about是动词短语,但是用在is后面时,应该这么用呢?
类似的一句还有:this subject is mainly to talk about....请问这种表述是对的吗?还是this subject mainly talk about...或者是this subject is mainly talk about?:)

在这里doing sth=to do sth

what we should do is to talk about.what ...is to do sth.这句型肯定是对的,后一句我没看到过,也不好说this subject mainly talks about...肯定对sb is to do sth./sth.is to be done我都看到过this subject is m...