Meilleure réponse !
   You must not do your homework before dinner.
   He might not  find a cheaper  car.
   You must do the washing-up.
   You should use my computer.
   They mustn't cut the grass.
   We should do shopping today .
   I musn't take my care to the garage .
   We can be allowed to go swimming .

3. will have
   had to

4. mustn't
    no, i needn't 
Merci merci merci 1000x tu vien de me sauver la vie :)))