You ......... help your parents.
must
You ........ shout in the library.
mustn't
You ....... return your library books on time.
must
You ........... cheat in tests at school.
mustn't
You .............. use your mobile phone at school.
mustn't
You ........... help others.
must
You ......... drop litter.
mustn't
You .............. listen to your teacher.
must
You .......... tidy your room.
must
You ........... do your homework.
must
You .......... eat in class.
mustn't
You .......... run at school.
mustn't
You .......... study at school.
must