Bonsoir !

Réponse : exercice n°1:

a) must

b) can

c) mustn't

d) je pense que c'est "can" mais je ne suis pas sûre

exercice n°2

a) Can I switch on my cell phone?

b) Students mustn't use the school computers to go on social media.

c) The teachers say we can't post offensive comments on the class blog

d) You needn't change your password every time you use the computer

e) Do you think visitors can take pictures in this museum ?

f) You needn't put your full name and address to use this app

J'espère que je n'ai pas fait de fautes et que cela t'as aidé !