MUST:
1. I must make sure cargoes reach their destination.
2. I must be careful on the staircase.
3. I must listen to the teacher.
4. We must build this house by autumn.
5. We must take care of nature.
6. We must wear out school uniform.
7. They must take care of their children.
8. She must go to work today.
9. He must stay care.
10. She must be polite to his parents.
MUSTN'T:
1. I mustn't make a mess.
2. I mustn't be late for school.
3. I mustn't forget my books.
4. You mustn't smoke in the room.
5. You mustn't run in school.
6. You mustn't talk loud in a hospital.
7. She mustn't eat at the lesson.
8. She mustn't use her mobile phone at the lesson.
9. He mustn't go to school if he's sick.
10. They mustn't use computer for more thah 4 hours straight.