Complete the sentences with must, mustn't or needn't. 1. you arrive in class on time. 2. you mobile phones in cla: .s. 3. you a dictionary to english as there are some in the classroom. 4. you be polite to the teachers. 5. do your homework on time. 6. bring sandwiches for lunch. there's a canteen. 7. go to afterschool activities. 8. you while the teacher is. 9. leave any money in the classroom. 10. bring your own paper. the school provides it.