把下列句子由单数变为复数或由复数变为单数.1、This is a book.2、That is a box.

问题描述:

把下列句子由单数变为复数或由复数变为单数.1、This is a book.2、That is a box.
3、Are those rulers?4、What are these.5、They are toys

These are books.

Those are boxes.

Is that a ruler ?

What's this ?

It's a toy.