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5.8: Modals of Strong Likelihood

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    375443
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    Must - Strong Likelihood
    Form Structure Examples
    POSITIVE Subject + must + base verb

    Subject + must be + adjective/noun
    "The parking lot at Crystal Cove is completely full. The hidden beach trail must be very popular today." "Sarah knows all these secret Orange County trails. She must be an experienced hiker."
    Must (strong likelihood): Shows a strong logical conclusion based on evidence or information available. Used when the speaker is very confident (90-95%) about their conclusion based on observable evidence, logical reasoning, or reliable information.
    NEGATIVE Subject + must not + base verb

    Subject + must not be + adjective/noun
     
    "Jenny isn't here yet. She must not have gotten the invitation to explore the Laguna Beach hidden caves." "This trail is completely empty on a Saturday. It must not be well-known."

     

    In modern American English, the contraction of "must not" to "mustn't" is uncommon.
    📝 Usage & Important Differences
    Difference: Must vs. Have To
    Must (strong likelihood): Shows a logical conclusion based on evidence
    "The parking is full. The trail must be crowded." (logical deduction) Have to (obligation): Shows necessity or requirement
    "We have to bring water for the desert hike." (necessity)
    Note about Questions: While "Must" questions are grammatically possible, they are not commonly used in modern American English. Native speakers typically use other forms like "Do we have to..." or "Do you think..." or "Is it likely that..." instead.

    5.8: Modals of Strong Likelihood is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

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