b Circle the correct form. Tick (V) if both are possible. We don't have to / mustn't go to school next week. It's the holiday. 1 You don't have to / mustn't cross the road when the traffic lights are red. 2 What do I have to / must I do when I finish this exercise? 3 The concert is free. You don't have to / mustn't pay. 4 We're late for the meeting. We have to / must go now. 5 You don't have to / mustn't leave the door open - the dog will get out. 6 I have to / must pay Jane back the money she lent me. 7 In Britain you have to / must drive on the left. 8 You don't have to / mustn't be tall to be good at football.