Improve your grammar

1. You must tidy up your room.
2. You mustn't smoke.
3. You must do your homework.
4. You mustn't play with fire.
5. You must be home on time.
6. You mustn't cheat in a test.
7. You mustn't turn the music too loud.
8. You must help in the house.
9. You mustn't annoy your little sister.
10. You mustn't bite nails.