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.
|
General declaration of fact. Paying taxes is something I normally do.
| |
I can pay my taxes.
|
Expresses ability. I have the means (funds) to pay.
| |
I might pay my taxes.
|
Expresses possibility, but not certainty. Maybe I will pay; maybe I won't.
| |
I will pay my taxes.
|
Expresses future intent. I resolve to do it at some later time.
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I should pay my taxes.
|
Expresses mild obligation. It is required, and I expect to comply.
| |
I could pay my taxes.
|
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.
|
(In this case), expresses reservation. If I had the money (but I don't). . .
| |
I must pay my taxes.
|
Expresses strong obligation. I am required and have to comply.
|
| Modal | Nature | Contraire | Exemples |
|---|---|---|---|
be able to
|
possibilité
|
cannotou be unable to
|
I was able to prevent the theft but I was unable to arrest the thief.
|
can
|
possibilité, capacité
|
cannot
|
Birds can fly; monkeys cannot.
|
permission
|
cannotou may not
|
Can I watch TV? No, you can't.
| |
could
|
possibilité, capactié
|
could not
|
Could there be a virus in this file? No, there couldn't; I ran the anti-virus.
|
possibilité (passé)
|
could not
|
Could dodo birds fly? No, they couldn't.
| |
permission
|
cannotou may not
|
Could I open the window? No, you may not.
| |
had better
|
conseil
|
had better not
|
You had better get moving, if you don't want to be late. You had better not be late.
|
have to, have got to
|
obligation (origine externe)
|
must not
|
I have to pay my taxes before the end of March. Origine externe: les lois de l'état.
|
must
|
nécessité, forte probabilité
|
cannot
|
A is bigger than B which is bigger than C, so A must be bigger than C. C cannot be bigger than A.
|
obligation (origine interne)
|
must not
|
Teacher to pupil: "You must come to school on time; you must not be late". Origine interne: le professeur qui parle décide.
| |
may
|
possibilité
|
cannot
|
It may rain. It can't possibly be 8 PM, I'm only half ready.
|
permission, requête
|
cannot
|
May I speak to Mrs X, please? No, youcan't, she's not in.
| |
might
|
possibilité (faible)
|
cannot
|
I might come to your party if I can get off work on time.
|
permission
|
may not
|
Might I borrow your laptop?
| |
ought to
|
devoir, conseil
|
ought not to
|
You ought to apologize to your sister for having hurt her feelings.
|
déduction logique
|
cannot, could not
|
That ought to be enough petrol to last us until we get to Lyons.
| |
should
|
conseil
|
should not
|
You should spend more time on your homework.
|
déduction logique
|
cannot, could not
|
