Is this a book? Yes, this is/Yes, it is.

[Mike MC]

Is it correct to use "this" in short answers?

Example:

John: Is this a book?
Jane: Yes, this is. (rather than Yes, it is.)

It there anything wrong with using "this" (pronoun) as the subject in a short answer?

 

[5jj]

It there anything wrong with using "this" (pronoun) as the subject in a short answer?

Yes.

 

[Mike MC]

Yes.

But aren't this (demonstrative pronoun) and it (subject pronoun) basically the same?

 

[Barque]

They aren't exactly the same. If you're answering the question "Is this a book?", you need "it".

If someone asked "What is a book?", you could pick one up and say "This is a book".

 

[emsr2d2]

In the same way that you would use "it" to refer to a previously mentioned noun, you do that to refer back to the pronouns "this/that" etc.

I have a blue mug. It's really pretty.
He saw a huge dog earlier. It was really scary.
This is my favourite cardigan. It's very comfortable.
That's not my uncle. It's my cousin.
What's that? It's a pen.