1. --- Can you swim in the river?

¡¡¡¡¡¡--- No, I _____.

¡¡¡¡A. mustn’t    B. may not     C. can’t      D. needn’t

¡¡¡¡2. --- £Íay I go swimming now?

¡¡¡¡¡¡ --- No, you ______. You must finish your homework first.

¡¡¡¡A. mustn’t   B. may not    C. couldn’t      D. needn’t

¡¡¡¡3. --- Excuse me. Where is the zoo?

¡¡¡¡¡¡ --- Sorry, I don’t know. Ask that policeman. He _____ know.

¡¡¡¡A. shall     B. may        C. need        D. would