1. You mustn't talk aloud in the library.
2. We should visit our grandparents more often.
3. You shouldn't drive too fast in the city.
4. She looks pretty sick. I think she should go to a doctor.
5. Hey I'm lost. Can you help me?
6. You have such a beautiful voice. You must sing for us!
7. That looks very expensive. It must have cost a fortune!
8. I can't believe that you failed your test!
9. I must have seen that movie eight times.
10. I can't understand what he's saying.