1. looks

2. would come

3. has changed

4. saw

5. Don't worry

6. Are you playing

7. to answer

8. haven't tidied

9. was watching

10. didn't take 

11. Has - ever gone

12. is being built

13. Will - be

14. returns

15. listening

16. will be sent

17. are - speaking

18. studying

19. to learn

20. doing

21. studying

22. going out

23. taking - to go

24. going

25. lying

26. do

27. goes

28. is sleeping

29. haven't seen

30. phoned

31. are trying

32. plays

33. had left

34. was discovered

35. practises

36. is knocking

37. have known

38. went

39. wears

40. knew

41. were watering

42. is talking

1 looks 

2 would come

3 has changed

4 saw

5 Don't worry

6 Are you playing

7 to answer

8 haven't tidied

vì dấu hiệu là for thì htht

9 was watching

dùng thì quá khứ tiếp diễn

10 didn't take

vì dấu hiệu là lát thì qkđ

11 Has - ever gone ever

chủ yếu thường dùng htht 

12 is building

dấu hiệu now thì httd

13 will - be 

có if

14 returns 

có as soon as

15 listening

có spend + v-ing

16 will be sent

17 are - speaking

18 studying

19 to learn

20 doing

21 studying

22 going out

23 taking - to go

24 going

25 lying

26 do

27 goes

28 is sleeping

29 haven't seen

30 phoned

31 are trying

32 plays

33. had left

34 was discovered

35 practises

36 is knocking

37 have known

38 went

39 wears

40 knew

41 were watering

42 is talking