have to do for learners of EnglishPowered by COBUILD
modal phrase & phrase
You use have to when you are saying that something is necessary or required, or musthappen. If you do not have to do something, it is not necessary or required. ⇒ He had to go to Germany. ⇒ We'll have to find a taxi. ⇒ You have to be careful what you say on telly. ⇒ They didn't have to pay tax.