1 Complete the rules. Use must/mustn't. You ... keep the room clean. (✔) play music after 10:00 am. (✔) put posters on the walls. (X) keep pets in the room. (X) make the bed. (✔)

Решение:

Используем 'must' для правил, которые обязательны, и 'mustn't' для запретов.

1. You must keep the room clean. (Обязательное правило)
2. You must play music after 10:00 am. (Обязательное правило)
3. You mustn't put posters on the walls. (Запрет)
4. You mustn't keep pets in the room. (Запрет)
5. You must make the bed. (Обязательное правило)