C. Choose the correct option. (have to for obligation /need to for necessity)
16. We need to / have to use a passport when we go abroad.
17. Dan and Rose have to / need to paint the bedroom because it looks old and dirty.
18. You don’t have to / need to pay for lunch. Let me take care of it.
19. It’s important! You have to / need to show your ID card before entering the library.
20. You have a fever, so you have to / need to go to bed early!