13. Complete the sentences with must, mustn’t, shouldor shouldn’t.
(Hoàn thành các câu với must, mustn’t, should hoặc shouldn’t.)
1 We ………… swim in the sea today. The weather is very bad and there’s a red flag.
2 The exams are finished now. You ………… relax and have a nice time with your friends.
3 You ………… eat in the library. That’s the rule.
4 We ………… arrive on time for lessons every day. It’s very important.
5 You ………… go to bed late. It isn’t a good idea.
6 We ………… cycle to school every day. It’s cheaper than the bus.
7 You ………… buy that book. It isn’t very good
1. mustn’t
2. should
3. mustn’t
4. must
5. shouldn’t
6. should
7. shouldn’t