Complete the exchanges with needn't or mustn't.

1. A: Doctor, I have a stomach ache again. B: From now on, you mustn't drink any coffee.
2. A: Nurse, I want to see the doctor right now! B: Sir, you mustn't shout in here.
3. A: I'm going to stop eating chocolate. B: You needn't do that. Just cut down a little!
4. A: I don't want to leave you on your own. B: You needn't worry about me. I'll be fine.
5. A: I took the tablets Steve gave me. B: You mustn't take antibiotics without a prescription!
6. A: I don't have a dress for the party. I'll buy one. B: You needn't do that. I'll lend you one of mine.