Have to / Must

 What is the difference between must and have to? : Must is a modal verb that translates to "duty" and is used in affirmative and negative. As a modal verb, it will follow the rules of all modal verbs, that is: → In affirmative sentences it will be followed by the infinitive without to. The semi-modal Have to is also used to express obligation.

How is the must used? : Must es un verbo modal que se traduce por "deber" y se utiliza en afirmativas y en negativas. Como verbo modal, seguirá las reglas de todos los verbos modales, es decir: → En frases afirmativas irá seguido de infinitivo sin to. El semimodal Have to también se usa para expresar obligación