Решение:
- The children mustn’t play football in the classroom.
- He doesn't have to make his lunch. His mum makes it for him.
- You don’t have to forget to brush your teeth before you go to bed.
- She mustn’t ride her motorbike without a helmet.
- You mustn’t steal or tell lies.
- Children have to drink lots of milk.
Ответ: 1. mustn’t; 2. doesn’t have to; 3. don’t have to; 4. mustn’t; 5. mustn’t; 6. have to.