VII.
1. have to follow (chủ ngữ số nhiều)
2. has to answer (chủ ngữ số ít)
3. don't have to go
4. Do .... have to buy
5. has to recycle (đại từ bất định được xem là chủ ngữ số ít)
6. has to come
7. have to wear
8. Does he have to
9. don't have to
10. have to stop
11. Do .... have to take
12. doesn't have to
13. had to leave (thì quá khứ đơn)
14. didn't have to do
15. don't have to do
VIII.
1. have to
2. must
3. shouldn't
4. don't have to
5. should (suggest: gợi ý)
6. have to (regulation: quy định)
7. mustn't
8. must
9. don't have to
10. should
IX.
1. a
2. b
3. d
4. c
5. b
6. d
7. a
8. b
9. c
10. b
