It is she that I am talking about.
It is the extraposition that I am interested in.
It is I to whom I was referring.
It was the text book with which I was struggling.
I was trying to find the name of those uses in it subject extraposition but failed to do so. So I changed them around just to see if they are extraposed.
5 That I am talking about is she.
6 To whom I was referring was I.
Well, they don't make much sense to me. So are they extraposed, or under some other category? Also, what is the name of this phenomenon or use?
P.S. Number 6 seems to make sense, but number 5 doesn't. Why is that? Also, someone said that I cannot put another subject after relative pronouns in this structure, and only the verbs can come after relative pronouns. So something like this:
It was I that (who) she was talking about. Not correct.
It was I that am correct. Correct.
Is what they are saying, that the subject cannot come after the relative pronoun, true?
