MODAL VERBS Modal Auxiliary: a set of verbs which are used with other verbs to express one of the modalities: possibility, ability, likelihood, certainty, obligation, etc., of the action
Trang 1MODAL VERBS (Modal Auxiliary): a set of verbs which are used with other verbs to
express (one of the modalities): possibility, ability, likelihood, certainty, obligation, etc.,
of the action English modals include: can, could, may, might, must, ought to, shall, should, will, would…
The use of modal auxiliaries:
CAN:
1 Ability (be able to, be capable of, know how to):
- He can speak English but he can not write it very well
2 Permission (be allowed to, be permitted to – can is less formal than may in this sense):
- Can I smoke in here?
3 Theoretical possibility (Contrast may = factual possibility)
- Anybody can make mistakes The road can be blocked
COULD:
1 Past ability: I never could play a banjo
2 Present or Future Permission: Could I smoke in here?
3 Present Possibility (theoretical or factual): We could go to the concert The road could
be blocked
4 Contingent possibility or Ability in unreal conditions: If we had more money, we could buy a car
MAY:
1 Permission (be allowed to – in this sense, (be allowed to – in this sense, may is more formal than can Instead of may not or rare mayn’t, the stronger mustn’t is often used in the negative to express prohibition): You may borrow my car if you like You mustn’t borrow my car (you are not allowed)
2 Possibility (usually factual): The road may be blocked
MIGHT:
Trang 21 Permission (rare): Might I smoke in here?
2 Possibility (Theoretical or factual): What you say might be true We might go to the concert
SHALL:
1 Willingness (on the part of the speaker in 2nd and 3rd person Restricted use): He shall get his money You shall do exactly what you wish
2 Intention (on the part of the speaker, only in 1st person): We shall overcome We shall
let you know our decision
3 Insistence (Restricted use): You shall do as you say He shall be punished
4 Legal & Quasi-legal injunction: The vendor shall maintain the equipment in good repair
SHOULD:
1 Obligation & Logical necessity (ought to): You should do as he says They should be home by now
2 ‘Putative’ use (after certain expressions, e.g., ‘it is a pity that…’, ‘I am surprised that…’): It is odd that you should say this to me I’m sorry that this should have
happened
3 Contingent use (1st person only and especially BrE) in main clause (=would): We should(would) love to go abroad (if we had the chance)
4 In rather formal real conditions: If you should change your mind, please let us know
WILL:
1 Willingness (used in polite requests): Will you please open the window? Will you give
me the key?
2 Intention (usually contracted ‘ll, mainly 1st person): I’ll write you as soon as I can
We won’t stay longer than 2 hours
3 Insistence (Stressed, hence no ‘ll contraction): He will do it, whatever you say He will keep interrupting me
4 Prediction (the similar meanings of other expressions for logical necessity and
habitual present The contracted form ‘ll is common):
Trang 3- Specific Prediction: The game will be finished by now.
- Time Prediction: Oil will float on water
- Habitual Prediction: He’ll (always) talk for hours if you give him the chance
WOULD:
1 Willingness: Would you excuse me?
2 Insistence: It’s your own fault You would take the baby with you
3 Characteristic activity in the past (often aspectual in effect): Every morning, he would go for a long walk (it was customary) John would make a mess of it (informal=it was typical)
4 Contingent use (in the main clause of a conditional sentence): He would smoke too much if I didn’t stop him
5 Probability: That would be his mother
MUST:
1 Obligation or Compulsion (in the present tense) (= be obliged to, have to – except in reported speech, only had to (not must) is used in the past) There are 2 negatives: (1) = not be obliged to: needn’t, don’t have to; (2) = be obliged not to: mustn’t
- You must be back by 10 o’clock
2 Logical Necessity (Must is not used in sentences with negative or interrogative meanings (can being used instead) Must can occur in superficially interrogative but answer-assuming sentences
- There must be a mistake (but there can not be a mistake)
- Mustn’t there be another reason for his behavior?
OUGHT TO:
Obligation; logical necessity or expectation: You ought to start at once They ought to
be here right now
Note: Ought to and should both denote obligation and logical necessity, but are less categorical than must and have to Ought to is often felt to be awkward in questions
Trang 4involving inversion, and should is preferred Still less categorical than ought is had better/best (plus bare infinitive):
A: Must you go?
B: Well, I don’t have to But I think I’d better (go)
THE MODALS and ASPECT:
The perfect and the progressive aspects are normally excluded when the modal expresses ‘ability’ or ‘permission’, and also when shall or will express ‘volition’ These aspect are freely used, however, with other modal meanings, e.g.:
Possibility: He may have missed the train He may have been visiting his mother He
can’t be swimming all day
Necessity: He can’t have been working He must have left his umbrella on the bus.
Prediction: I must be dreaming You must have been sitting in the sun The guests will
have arrived by now John will still be reading his paper
SEMI-MODALS: DARE, NEED, USED TO
DARE & NEED
When used as modals, they have the same meanings as when they are followed by a “to”-infinitive clause However they are normally used as modals only in negative sentences and in questions:
Nobody dare disturb him
How dare you speak to me like this?
Need you go so soon?
With his father, he need not fear
Inflected forms: Unlike other modals, dare has some inflected forms which are
occasionally used:
When it comes, she dare not express her feelings
Trang 5He dare not take his eyes off his assailant.
He dared not show he was pleased
Use with other modals: Dare can be used with will, would, should and might:
Nobody will dare override what the towns decide
I wouldn’t dare to go to Europe
Use with ‘do’:
We don’t dare examine it I didn’t dare speak or move
USED TO:
- Has no inflected forms, and can not be used with other modals:
She used to get quit cross with her son
- Can be used with ‘DO’ to say something happened regularly or existed in the past although it no longer happens or exists: They didn’t used to mind what we did
- Is used to describe repeated actions in the past: I used to go to school on this road
- Can describe past states and situations: Did you used to play with your train?
- Not common in negative structure Instead, put ‘didn’t’ in front of it: Didn’t they used
to mind?
-Social interactional uses of modals:
1 Making request:
Will/would/can/could you help me with this math problem?
2 Giving advice:
Trang 6You should see a doctor.
Logical Probability uses of modals:
It could rain tomorrow > It is possible that it will rain tomorrow
Other uses of modals:
Ability: I can speak English.
Desire: She would like to travel around the world.
Offer: Would you like anything to drink?
Preference: He would rather study languages than mathematics.
Periphrastic modal counterparts:
Multiword forms ending in ‘to’, which function semantically much like true modals, are called periphrastic modals:
Modals Periphrastic Modals
Can - be able to
Will - be going to, be about to
Must - have to, have got to
Should, Ought to - be to, be supposed to
May - be allowed to