VI. Correct the verb tense
1. have seen ( Thì HTHT, dấu hiệu: recently )
2. was - wanted ( Thì QKĐ )
3. am working ( Thì HTTD, dấu hiệu: Please be quiet! )
4. was working ( Thì QKTD, dấu hiệu: at 4pm yesterday )
5. listened ( QKĐ, dấu hiệu: last night )
6. has painted ( HTHT, dấu hiệu: since )
7. were sitting - was doing ( QKTD )
8. broke - stole - were dancing ( QKĐ - QKTD )
9. had done ( QKHT, dấu hiệu: before )
10. have been planted - stopped ( HTHT - QKĐ, dấu hiệu: since )
11. is singing ( HTTD, dấu hiệu: Listen! )
12. was built ( bị động QKĐ, dấu hiệu: 2 years ago )
13. has just cut ( HTHT, dấu hiệu: just )
14. was watching ( QKTD, dấu hiệu: at 8 last evening )
15. don't eat ( HTĐ, diễn tả sự thật hiển nhiên )
16. was speaking ( QKTD, Tại sao bạn không lắng nghe trong khi tôi đang nói chuyện với bạn )
17. is ( Hãy im lặng! Giáo viên đang tức giận )
18. will speak ( TLĐ; dự định )
19. am having ( HTTD )
20. haven't received - left ( HTHT - QKĐ, dấu hiệu: since )
21. have you studied ( HTHT: Bạn đã học ở ngôi trường này bao lâu? )
22. have not seen ( HTHT, dấu hiệu: for )
23. were you doing - rang ( QKTD - QKĐ )
24. speak ( HTĐ: diễn tả sự thật hiển nhiên )
25. was ( QKĐ, dấu hiệu: ago )
26. discovered ( QKĐ, dấu hiệu: ago )
27. left - have not heard ( QKĐ - HTHT )
28. build - fly ( HTĐ: diễn tả sự thật )
29. have lost ( HTHT )
30. Have you received ( HTHT, dấu hiệu: yet )
31. has not smoked ( HTHT, dấu hiệu: for )
32. saw - was waiting ( QKĐ - QKTD )
33. has been ( HTHT, dấu hiệu: since )
34. are preparing ( HTTD, dấu hiệu: at the moment )
35. has worked ( HTHT: so far )
36. built ( QKĐ: ago )
37. was having - called ( QKTD - QKĐ )
38. came - has already bought ( QKĐ - HTHT: already )
39. had ended ( QKHT, dấu hiệu : by the time )
40. will have built ( TLHT: by June next year )