Must or Have to

Must can only be used to talk about the present and future.  For all other tenses you need to use a form of the verb  to have to.

Many non-native speakers prefer to use must, bus sometimes this can sound unnatural.  Native English speakers often use have to.

For the basic rules of when to use must and when to use have to click on the diagram below..

Then why not test yourself with our exercises: QuizGap-FillWorksheet.