must
must means “must + verb: strong necessity; must not = prohibition”. Must expresses strong necessity, often rules or the speaker's own feeling: You must wear a seatbelt. Formation: must + V · must not = forbidden
must + verb: strong necessity; must not = prohibition
A2Formation
must + V · must not = forbidden
Explanation
Must expresses strong necessity, often rules or the speaker's own feeling: You must wear a seatbelt. I must finish this today. Must not means something is forbidden: You must not use your phone here. Like can, must never changes form and takes no to.
Examples
Note
Two negatives, two meanings: must not = forbidden; don't have to = not necessary. For past obligation, use had to (must has no past form).
FAQ
must — what does it mean and how is it used?
must + verb: strong necessity; must not = prohibition. Must expresses strong necessity, often rules or the speaker's own feeling: You must wear a seatbelt. I must finish this today. Must not means something is forbidden: You must not use your phone here. Like can, must never changes form and takes no to.
must — how do you form it?
must + V · must not = forbidden
must — any usage notes?
Two negatives, two meanings: must not = forbidden; don't have to = not necessary. For past obligation, use had to (must has no past form).