You must do your homework. = tu dois faire tes devoirs (obligation)
Can I use your dictionary?  = je peux me servir de ton dictionnaire? (permission)
You don’t have to come today. = Tu n'as pas besoin de venir aujourd’hui (absence d'obligation)
You must listen to me now! = tu dois m'écouter maintenant! (obligation)
 You needn't come today. = tu n'es pas obligé de venir aujourd’hui (absence d'obligation)
voila des phrases faites "maison".
-You have to finish your work before next Monday !
-You have to eat all your spinach !

You're aload to use a dictionnary for this test.
You can have more potatoes if you want to.

Absence d'obligaiton:
You don't have to help her.
You don't have to wear a coat today.