The key answer of exercise 2

a)

1. don't you
2. were you
3. didn't you
4. haven't you
5. aren't you
6. doesn't he
7. haven't you
8. wouldn't you

b)

1. isn't he
2. do you
3. is it
4. doesn't he
5. didn't they
6. has she
7. aren't I
8. won't you
9. would I
10. have you

c)

1. Your sister's in my class, isn't she?
2. You're younger than me, aren't you?
3. You don't like cheese, do you?
4. Your brother lives abroad, doesn't he?
5. You studied physics, didn't you?
6. We've been here before, haven't we?
7. You wouldn't do that, would you?
8. The flight won't be cancelled, will it?