Use 'must' or 'mustn't to tell the rules
We mustn’t sit on the train floor.
Use 'must' or 'mustn't to tell the rules
We must sit still.
Use 'must' tell the rules
We must keep off the grass.
Use 'mustn't tell the rules
We mustn't litter.
Use 'must' tell the rules.
We must keep quiet.
Use 'mustn't' tell the rules.
We mustn't spit.
Use 'mustn't' tell the rules
We mustn't feed the monkeys.
