You must/mustn't run at school.
Mustn't
You must/mustn't be quiet in the library.
Must
You must/mustn't use your mobile phone at school.
Mustn't
You must/mustn't walk on the grass.
Mustn't
You must/mustn't listen to your teacher.
Must
You must/mustn't go fishing in the lake.
Mustn't
You must/mustn't talk in class.
Mustn't
You must/mustn't do your homework.
Must
You must/mustn't sleep in class.
Mustn't