1. B => bỏ "to"
2. A => asked / told
3. D => bỏ
4. C => I would like
5. C => she liked
6. A => asked
7. B => enjoyed
8. D => the next Wednesday
9. A => it was
10. C => there were
11. D => he would
12. B => wanted
13. B => if Hong
14. C => worked
15. D => didn't
16. D => that
17. D => bỏ
18. A => he'd (he would)
19. B => had to write
20. B => not to