Chia động từ trong ngoặc :

1. saw/ was waiting

2. has been

3. has taught/graduated

4. doesn't watch

5. met

6. reported / had captured 

7. thanked

8. has stolen

9. had lived/broke

10. was

11 am

12. was / had been

13. has driven/knew

14. speak

15. wags/sees

16. were .. doing/rang

17. have .. seen

18. hadn't seen

19. got

20. will leave/knows

21. was playing/arrived

22. will come /see

23. will come / Will ..be 

24. will come

25. will .. spend

27. haven't been living

28. have never forgotten /have just told

29. are preparing

30. stayed /rode

31. told/had visited

32. has worked

33. worked

34. build/fly

35. have lost/Can

36. hasn't smoked

37. arrived/has just gone

38. have ..been

39. Have .. received

40. joined /was

41. Have .. remembered / forgotten

42. had studied

43. wrote

44. left / haven't heard

45. Did .. speak / haven't seen / couldn't remember / saw 

46. was playing

47. discovered

48. will have finised

49. will have been living

50. did/ die / don't know / die