Complete the sentences with “must, mustn't, should” or “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.