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could - definition and synonyms

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modal verb strong    could pronunciation in British English
/kʊd/ weak    could pronunciation in British English
Could is usually followed by an infinitive without ‘to’: I’m glad you could come. Sometimes it is used without a following infinitive: I came as quickly as I could.
Could does not change its form, so the third person singular form does not end in ‘-s’: She could play the violin when she was six.
Questions and negatives are formed without ‘do’: Could he help you?I could not breathe.
The negative form could not is often shortened in conversation or informal writing to couldn’t: I couldn’t find her phone number.
Could is often used in question tags: They couldn’t see us, could they?
Could has no tenses, no participles, and no infinitive form.
There is no past tense, but could have followed by a past participle is used for referring to something in the past that was not real, or something that may possibly have been real: I could have been killed.What was that noise? Could it have been the wind?
Could is used as the past tense of can when it means that someone had the ability to do something, or that something was possible: The Roman army could march 30 miles in a day.
But if you want to say that someone actually succeeded in doing something, use was/were able to: Thanks to this grant, we were able to buy new equipment.
  1. 1
    used as the past tense of ‘can’

    Renee could already read when she was four.

    In the distance I could see a cloud of smoke.

  2. 2
    spoken used in polite requests, or when offering or suggesting something

    Could I have a glass of water?

    Could you post this letter for me?

    I wonder if we could borrow your lawnmower?

    Synonyms and related words
    See also can
  3. 3
    used for saying what is possible
    1. a.
      used for saying that something is possible or that it may happen

      We could still win – the game isn’t over yet.

      In a situation like this, anything could happen.

      could easily:

      You could easily lose your way in the dark.

      Synonyms and related words
    2. b.
      spoken used for suggesting to someone a possible course of action, especially when they are in a difficult situation

      You could come and stay with us.

      could always:

      You could always sell the cottage if you need some extra cash.

  4. 4
    spoken used for showing that you are annoyed at the way someone has behaved

    How could you be so cruel!

    They could at least have said they were sorry.

  5. 5
    spoken used for emphasizing how angry, happy, bored etc you are

    It’s all Helen’s fault. I could strangle her!

    When I heard the news, I was so happy I could have cried.

    Synonyms and related words
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to manipulate someone psychologically so that they begin to question their own perceptions and memories

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Dunning-Kruger effect

the phenomenon by which an incompetent person is too incompetent to understand his own incompetence

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