Rewrite the following sentence in the plural from

II rewrite the following sentence in the plural from 

1 what's this ? - it's a stereo 

2 what's that ? - it's an armchair =>

3 who's he ? -he's a teacher=>

4 i'm a student =>

5 is this your pencil ? yes , it is =>

6 is that her schoolbag ? yes , it is=>

7 there is a school in my city =>

8 that is my bookshelf =>