Is this a book?Yes,it is.  No,it isn't

Is your classroom big?   Yes,it is.    No,it isn't.
Are there any trees behind the house?Yes,there are.   No,there aren't.
Do you go to school on foot?   Yes,I do.     No,I don't.
Does he work at the hospital?  Yes,he does.   No,he doesn't.
少一句I’m　a　student．Are you a student?Yes, I am. No, i am not.