I. Choose the correct word or phrase in each sentence.
1. There’s someone at the door. It can / must be the postman.
2. Don’t worry, you don’t have to / mustn’t pay now.
3. It was 5 o’clock an hour ago. Your watch can’t / mustn’t be right.
4. In my opinion, the government might / should do something about this.
5. I suppose that our team must / should win, but I’m not sure.

II. Rewrite each sentence so that it contains some of these modal verbs: can, could, must, have to or should (including negative forms):

1. I’m sure that Helen feels really lonely.
2. You’re not allowed to park here.
3. It would be a good idea if Harry took a holiday.
4. Do I need a different driving licence for a motorbike?
5. Mary knows how to stand on her head.

III. Complete each sentence so that it contains might, might not, must, mustn’t, can’t or can. More than one answer may be possible.
1. I   ______ forget to phone Julie tonight.
2. Sue says she’s stuck in traffic and she ________ be late.
3. Tell Peter he _____ stay the night here if he wants to.
4. Me learn to fly! You ______ be joking!
5. Don’t be silly. You ___________ expect me to believe you!
6. Tim ___________ have got your letter as he doesn’t know your address.