1.This is my book.2.That is my pen.3.Yes,it is.

问题描述:

1.This is my book.
2.That is my pen.
3.Yes,it is.

These are my books
Those are my pens
yes,they are

These are my books.
Those are my pens.
Yes,they are.

1These are our books.
2Those are our pens.
3 yes they are.