3)

1. don't have to

2. mustn't

3. have to

4. have to

5. mustn't

4)

1. have to

2. have to

3. must

4. have to

5. must

5)

You must arrive at school on time.

You have to be quiet in the corridor.

You needn't eat snacks in class.

You must hand in homework on time.

You have to have lunch in the canteen.

You needn't use a mobile phone in class.

You have to wear a school uniform.