Sure! Here are the completed sentences:

**Ex1: Complete the sentences with must, mustn’t or don’t have to.**

1. We **must** wear a uniform for sport lessons. We wear our own sports clothes.
2. At our school, we have to wear a uniform. We **mustn't** wear jeans or T-shirts.
3. We **mustn't** walk in the corridor. Running is dangerous.
4. We **must** take our books back to the library so other students can read them.
5. We **mustn’t** talk in the classroom. We have to be quiet.
6. We **don’t have to** go to homework club but lots of people do.

**Ex2: Correct the mistakes in three of the sentences. Write correct in the two that are correct.**

1. You **don't have to** bring anything because the teacher will give you what you need.
2. It will be cold, so you must wear warm clothes! (correct)
3. You **mustn't** spend so much time on the internet! (correct)
4. Tomorrow night you must come to my house. To get to my house you have to take the number 1 bus. (correct)
5. You **don't have to** bring anything because I've got everything.

Let me know if you need further assistance!