must

/mʌst/

modal verb

  1. Used to say that something is necessary or that someone is required to do it.

    A1

    followed by the base form of a verb; no third-person -s

    • "You must wear a seat belt."A1
    • "We must leave now if we want to catch the train."A2
    • "Visitors must show their passports at the entrance."A2
    • "Applicants must demonstrate relevant professional experience."B2

  2. Used to give a strong recommendation or express what you consider essential.

    A2

    followed by the base form of a verb

    • "You must try this cake."A2
    • "You must visit the museum while you are here."B1
    • "Anyone interested in modern architecture must see this exhibition."B2

  3. Used to express a strong belief or logical conclusion about something.

    B1

    must be or must have + past participle

    • "She must be tired."A2
    • "He must be at home because his car is in the driveway."B1
    • "They must have missed the bus."B1
    • "The lights are on, so someone must still be working."B2

noun

  1. Something that is essential or extremely important to do, see, or have.

    B1

    countable; usually used as a must or must-have

    • "This book is a must for students."B1
    • "A good camera is a must for professional photographers."B2

Common mistakes

  • You must to leave now.→You must leave now.

    Must is followed directly by the base form of the verb, without to.

  • You don't must leave.→You mustn't leave.

    Use mustn't for prohibition. Use don't have to when something is not necessary.

Collocations

must bemust havemust domust seemust-seea must

Word family

must-havemustn'tmust've