Ответ:

1. In the Czech Republic you mustn't smoke in restaurants.

2. If you want to pass the exam, you should start studying.

3. You must be 18 if you want to drive a car.

4. You shouldn't smoke so much, it is bad for you!

5. All the staff must show their identity cards when they enter the building.

6. My mum shouldn't work so hard, she looks tired.

7. You mustn't touch the paintings in the gallery.

8. All the visitors should go to the reception when they arrive.

9. You must wear a coat, it is cold outside.

10. We mustn't be late for the meeting, it is very important.

11. What do you think I should give dad for his birthday?

12. We mustn't forget to send the letter, it is important!

13. If Mary wants to get the job, she must pass a difficult language test.

14. I don't feel well, I must stay at home.

15. You mustn't bring food and drinks to the library.