1, I am not a doctor.

2, My father isn't at home.

3, They are not happy today.

4, I wasn't at school yesterday.

5, They weren't teachers five years ago.

6, Jimmy doesn't like milk.

7, We don't play computer games .

8, Our teacher didn't come to school yesterday.

9, He hasn't come back yet.

10, We haven't finished our homework.