4 Complete the sentences with these phrases and must or mustn't. buy a ticket stand on the desks They....... on the farm. ✓ 1 You mustn't drop litter in the park. * 2 3 We........ in the library. x 4 She ....... at school. * 5 I...... at home. ✔ 6 You...... drop litter talk on the bus. ✔ shut the gates tidy my room​