1. Speak slowly. I **can't** understand you!
2. I'm sorry, I **have to** wait. I have to go to my lesson.
3. I **don't have to** be late for school. I've got an exam this morning.
4. You **don't have to** come with me to the doctor. I'm fine on my own.
5. I **don't have to** go to bed early because it's the weekend.