Introduction:

Expressing necessity.

Structure:

subject + must have + past participle
subject + have got to + verb (simple form)
Consider: I have gotten your email.
I have got to go.

Examples:

I have got to go to work.
I haven’t got to go to work.
Have I got to go to work?
Haven’t I got to go to work?
I must go to the meeting.
I mustn’t (must not) go to the meeting.
Must I go to the meeting?
Mustn’t I go to the meeting?