But, hasn't got to is less commonly used than doesn't have to.
Students MUST wear their uniform correctly everyday at school.
You could also use have to wear here with a similar meaning to must wear.
This is what dictates the modal factor.
You could also use might, may, could and should.
Either , talk to an expert at 800-710-0455, or us! Question 2 If it rained last night the match will have been cancelled.