Lesson 24 of 46

Meanings of modal verbs

Choose between must, have to, should, may, and might.

The rules

  1. 1.Must = strong obligation or a strong conclusion. Have to = obligation from outside rules. Should = advice.
  2. 2.Can/could = ability or permission. May = formal permission or possibility. Might = weaker possibility.
  3. 3.Must not (mustn't) = forbidden. Do not have to = not necessary. They are very different.
  4. 4.For politeness, prefer could/would: "Could you help me?" sounds softer than "Can you help me?".

Common mistakes and fixes

Incorrect: You mustn't come tomorrow; it is optional.

Correct: You don't have to come tomorrow; it is optional.

Mustn't means forbidden.

Incorrect: You must to submit the form.

Correct: You must submit the form.

No "to" after a modal.

Incorrect: I might to be late.

Correct: I might be late.

Modal + base verb.

Watch out: Don't have to = optional. Mustn't = not allowed.

Quick quiz

1. Visitors ___ park here. It is private.
2. You ___ see a doctor — you look ill.
3. It ___ rain later, so take an umbrella.

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