Complete the sentences with must or mustn't.
1. Hurry up, James-we ..... be late.
2. I ..... remember to phone Sonia tonight.
3. Here's your present. You .... open it before your birthday!
4. You ...... forget to lock the door before you leave.
5. If you go to London, you ..... go to the Trocadero-it's great!
7. Vy old dictionary is useless - i ..... buy a new one.