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