a) 1. is, has

2. don't believe

3. is practising

4. walk

5. is, gets up

6. like

7. enjoys

8. practise

9. play

10. are not

11. washes

12. doesn't smoke

13. doesn't know

14. has, sells

15. wear

16. is washing, washes

17. don't do

b) 1. usually study

2. are having

3. gets

4. always meets

5. studies, is studying

6. goes

7. is raining

8. takes, is going

9. are not swimming

10. am cooking, am watching

11. doesn't do, does

12. ask

13. is climbing