Modal auxiliary verbs are used to moderate the main verb, that is to enhance or restrict the verb to a certain context.
The most common modal auxiliaries in English are:
can could | may should | might will | must would |
Notice the usage of modals in the following sentences:
I pay my taxes.
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General declaration of fact. Paying taxes is something I normally do.
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I can pay my taxes.
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Expresses ability. I have the means (funds) to pay.
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I might pay my taxes.
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Expresses possibility, but not certainty. Maybe I will pay; maybe I won't.
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I will pay my taxes.
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Expresses future intent. I resolve to do it at some later time.
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I should pay my taxes.
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Expresses mild obligation. It is required, and I expect to comply.
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I could pay my taxes.
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Expresses possibility. If I have nothing else to do with the money, I might pay taxes.
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I would pay my taxes.
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(In this case), expresses reservation. If I had the money (but I don't). . .
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I must pay my taxes.
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Expresses strong obligation. I am required and have to comply.
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Modal | Nature | Contraire | Exemples |
---|---|---|---|
be able to
|
possibilité
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cannotou be unable to
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I was able to prevent the theft but I was unable to arrest the thief.
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can
|
possibilité, capacité
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cannot
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Birds can fly; monkeys cannot.
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permission
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cannotou may not
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Can I watch TV? No, you can't.
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could
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possibilité, capactié
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could not
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Could there be a virus in this file? No, there couldn't; I ran the anti-virus.
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possibilité (passé)
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could not
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Could dodo birds fly? No, they couldn't.
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permission
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cannotou may not
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Could I open the window? No, you may not.
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had better
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conseil
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had better not
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You had better get moving, if you don't want to be late. You had better not be late.
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have to, have got to
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obligation (origine externe)
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must not
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I have to pay my taxes before the end of March. Origine externe: les lois de l'état.
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must
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nécessité, forte probabilité
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cannot
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A is bigger than B which is bigger than C, so A must be bigger than C. C cannot be bigger than A.
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obligation (origine interne)
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must not
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Teacher to pupil: "You must come to school on time; you must not be late". Origine interne: le professeur qui parle décide.
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may
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possibilité
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cannot
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It may rain. It can't possibly be 8 PM, I'm only half ready.
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permission, requête
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cannot
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May I speak to Mrs X, please? No, youcan't, she's not in.
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might
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possibilité (faible)
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cannot
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I might come to your party if I can get off work on time.
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permission
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may not
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Might I borrow your laptop?
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ought to
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devoir, conseil
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ought not to
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You ought to apologize to your sister for having hurt her feelings.
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déduction logique
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cannot, could not
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That ought to be enough petrol to last us until we get to Lyons.
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should
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conseil
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should not
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You should spend more time on your homework.
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déduction logique
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cannot, could not
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