Underline the correct form. Example: You must / don’t have to tidy your room. It’s a mess. 1 You don’t have to / mustn’t swim there. It’s dangerous. 2 I haven’t to / don’t have to do my homework. It’s Saturday. 3 She must / mustn’t practise the piano tonight. She’s not very good. 4 They have to / don’t have to be home early. They’re very young. 5 We mustn’t / don’t have to buy tickets – entrance is free. 6 You can’t / must go to the party. It’s too late.