5. Choose the correct option: have to / don't have to.

Solution:

• 1. You don't have to water the plants. I've already done it. (No obligation as the task is already completed).
• 2. We have to wear a uniform at school. It's a rule. (Obligation due to a rule).
• 3. He doesn't have to get up early tomorrow because it's Sunday. (No obligation as it's a non-working day).

Final Answer: 1. don't have to, 2. have to, 3. doesn't have to