Ex3:
1. B
2. D
3. D
4. C
5. A
6. B
7. D
8. B
9. A
10. A
11. C
12. D
13. D
14. B
15. C
16. A
17. D
18. B
19. C
20. A
Ex4:
1. goes
2. swim
3. didn't use to
4. seeing
5. be
6. did she use to
7. to work
8. didn't use to
nhớ cho mình trả lời hay nhất nhé, chắc chắn đúng nha