You mustn't arrive late. You must do your homework. You must help your classmates. You mustn't copy other students' homework. You mustn't eat in class. You must study hard. You mustn't talk during lesson. You mustn't throw litter on the floor. You mustn't write on the walls or desks. You must be polite. You must put your hand up to ask a question. You must respect your teacher. You mustn't use your phone in class. You must be in your classroom by 8.25. You mustn't run in the school.
