1. Saw/ was waiting

2. Has been

3. Has taught/ graduated 

4. Doesn't watch

5. Met

6. Was/ have known 

7. Won't come

8. Stole

9. Spend

10. Was

11. Am

12. Likes

13. Has driven/ knew

14. Speak

15. Wags/ sees

16. Were you doing/ rang

17. Is singing

18. Haven't seen

19. Has cut

20. Will leave/ knows

21. Was playing/ arrived 

22. Will come/ see

23. Will come/ are

P/s: trong ngoặc "(...)" là dấu hiệu nhận biết để chia thì

1. Saw - was waiting (yesterday là thì quá khứ đơn)

2. Has been (since last year)

3. Has taught - graduated (since...in 1980)

4. Doesn't watch (every night)

5. Met (ago)

6. Was -  have known(since)

7. Won't come (tomorrow)

8. Stole

9. Spend (every day)

10. Was (last month)

11. Am

12. Likes

13. Has driven -  knew

14. Speak

15. Wags - sees

16. Were you doing - rang (last night)

17. Is singing (listen!)

18. Haven't seen (since last Monday)

19. Has cut

20. Will leave - knows

21. Was playing - arrived (last night)

22. Will come - see

23. Will come - are