MODAL VERBS UNIT 4 (6º)
We use have to / must / should + infinitive to talk about obligation, things that are necessary to do, or to give advice about things that are a good idea to do.
Must and have to are both used for obligation and are often quite similar. They are both followed by the infinitive.
I must go now. / I have to go now.
Are these exactly the same?
Well, almost. We often use must for more personal opinions about what it is necessary to do, and have to for what somebody in authority has said it is necessary to do.
I must remember to get a present for Daisy. (my opinion)
You have to look after their hair regularly. (dog experts say so)
Do you have to wear a tie for school? (asking about school rules)
