Use must/mustn’t, may, can/can’t, should/shouldn’t, need/needn’t. you talk aloud in the library. we visit our grandparents more often. you drive too fast in the city. she looks pretty sick. i think she go to a doctor. hey i'm lost. you help me? you have such a beautiful voice. you sing for us! that looks very expensive. it have cost a fortune! i believe that you failed your test! i have seen that movie eight times. i understand what he's saying.

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.