1.In a hospital
No smoking is allowed.
No shouting is allowed.
2.During an exam
Students mustn't talk with others.
Students mustn't peek others' answers.
3.At a concert
Audiences don't be allowed to shout at a concert.
Audiences don't be allowed to disturb the concert.
4.At a beach
Parents can't leave childrens alone.
People can't fight with others.