1. has he stopped
2. is looking; hasn't found
3. is
4. are you studying
5. They have just given...
6. is knitting
7. Have you had; don't eat
8. are planting
9. Are you going
10. has foung, is giving (is going to give)
11. have you been
12. Have you seen
13. are you looking
14. is looking forward
15. is going; is not going
16. Has Mike left
17. Have they paid
18. have you known
19. is making/makes
20. has done; is taking
21. am having
22. has never travelled
23. have always had
24. has never owned