Must is a modal verb used to show obligation.  Like all modal
verbs, must is followed by a base verb:


MUST        +        BASE VERB

Examples:

  • He must go to class today.
  • They must work tomorrow.


Must is also used to show possibility, and is used in situations
where the speaker is very certain.

Examples:

  • He ate 3 pieces of cake.  He must like cake.
  • They worked for 12 hours today.  They must be tired.


Here are some modal verb tests that use must:

Modal Verbs of Obligation
Modal Verbs for Possibility Test
Modal Verbs for Possibility Test 2
Modal Verbs Test
Modal Verbs Test 2
modals
modal verbs

Must

Business English
Modal Verbs Tests