1. You must work harder if you want to pass the exam.
2. I don’t want anyone to know. You mustn't tell anyone.
3. Can you please open the door?
4. Can I go out tonight? No, you must study English.
5. We haven’t got much time. We must hurry.
6. He can't play tennis very well now but he couldn't play really well when he was young.
7. Tom can drive but he hasn’t got a car.
8. The boy fell into the river but fortunately we could rescue him.
9. We haven’t got enough food at home so we must go shopping today.
10. She wasn’t at home when I phoned but I could contact her at her office.
11. I can’t stay in bed tomorrow morning because I must work.
12. You mustn't touch that switch. It’s very dangerous.
13. Can you post this letter for me?
14. Brian has got three houses, six cars, a yacht. He can be very rich.
15. You’ve only just had dinner. You can't be hungry.
Họk tốt ~