Bonjour,
Réponse :
a. In British schools, pupils must wear a uniform.
b. They mustn't wear any jewelry.
c. At school, pupils must respect the rules.
d. Girls mustn't wear short skirts and the schoolbadge must be visible.
Pupils mustn't wear boots or canvas shoes, they must wear formal shoes.
Explications :
must : pour ce que l'on doit faire
mustn't : pour ce que l'on ne doit pas faire
