practical grammar I summer term MODAL VERBS (Graver, S&W)
auxiliary verbs
primary auxiliary: be; have; do
modal auxiliary: will, would, shall, should, can, could, may, might, must, ought to, used to, dare, need
[1] There are only thirteen (ten? twelve?) modal auxiliary verbs, but they are used with very great frequency and in a wide range of meanings. They express concepts or attitudes relating to recommendation, obligation, necessity, and prohibition; permission and refusal; possibility, expectation, probability and certainty; promise and intention, ability and willingness.
[2] There are four paired forms - can, could; may, might; shall, should; will, would;
and five single forms - must, ought, (need, dare, used to).
The three latter verbs are nowadays called semi-modals, i.e. verbs that share some of the characteristics of modals.
[3] The principal distinctive formal features of modal verbs are the following:
Modals never use other auxiliaries when forming questions or negatives. To form interrogatives we use inversion, to form negatives we use not after the modal and before the verb. Modals are auxiliaries for themselves: Will you come? You mustn't worry so much.
Modals never change form. They do not have -ed, -s, or -ing endings: Maria may join us.
(c) Modals are followed by the infinitive of a verb without to (except in the case of ought):
I may meet her tomorrow.
I ought to speak to your father.
[4] The modal verbs (including dare and need as modals) have no infinitive form, and no participle forms; no other forms then the ones listed, and all modals are therefore, to varying degrees, 'defective' verbs.
Hence the need on occasion for a number of more or less synonymous expressions having a fuller range of forms. These verbs always use to. They include:
be able to, have to, are / is / was to, be allowed to, be supposed to, manage to:
I'm supposed to have let them know my decision by today.
Will we be allowed to bring our own food?
I'd like to be able to speak English fluently. (infinitive)
No one has been able to solve the problem. (present perfect)
I'm having to read this very carefully. (present progressive)
You will have to pay extra for a single room. (infinitive without 'to')
[5] The modal verbs are also limited in their range of time reference. When used with the 'present' infinitive of the main verb, they generally have a present or future time reference:
He can or could
may or might
shall or should
must
ought to help you (e. g.) immediately, later
The use of the past forms could, might, would, should, suggests a more tentative attitude on the part of the speaker. In requests, it represents what is commonly called the 'polite' form:
'Would you do me a favour?'
'Could you pass the sugar, please?'
[6] It is misleading to regard could as the equivalent in past time of can, might as the equivalent of may, etc. Of the four past tense forms (could, might, would, should), only the first three are used to refer to past time when followed by a present infinitive, and then only within a restricted range of meanings:
He could speak several languages by the time he was ten.
He was very independent, and would never ask for help.
Try as he might, he couldn't get the car to start.
The use of the four past tense forms is, however, automatic in the sequence of tenses in reported speech.
The five single forms must, ought to, dare, need, used to, may be left unchanged in reported speech:
PRIMARY AND SECONDARY USES OF MODALS
MODAL VERBS have two main uses: primary and secondary. In their primary use, they closely reflect the meanings often given first in most dictionaries and are defective, that is, they need other full verbs to make up their 'missing parts'. For example, must has no 'past' form, so we refer to obligation in the past with had to:
I must go (now). I had to go (then).
Their past forms (if available) in the vast majority of cases refer to real past.
The primary meanings of modal verbs are as follows:
- can/could relate mainly to ability or permission: I can lift 25 kg.
- may/might relate mainly to permission: You may leave early.
- will/would relate mainly to prediction: It will rain soon.
- shall after I/We relates mainly to prediction: Can we find our way home? - I'm sure we shall.
- should/ought to relate mainly to escapable obligation (recommendation): You should do as you're told.
- must relates mainly to inescapable obligation: You must be quiet.
- needn't relates to absence of obligation: You needn't wait.
In their secondary use, all modal verbs (except shall) express degrees of certainty, with might expressing the highest degree of uncertainty and can't/must expressing the highest degree of certainty. In their secondary use, modal verbs have only two forms:
present: You must be right.
perfect and past (always expressing `unreal past'): You must have been right.
SEMI-MODALS
The verbs need, dare and used to are sometimes called semi-modals because they can behave like modal verbs or like full verbs, for example:
You needn't leave yet. (need behaving like a modal verb)
You don't need to leave yet. (need behaving like an ordinary verb)
Used always takes the to-infinitive and occurs only in the past tense. It may take the do-construction, in which case the spellings use and used /ju:st/ both occur:
He didn't use to smoke.
The interrogative construction Used he to smoke? is <esp BrE>. Did he use(d) to smoke? is preferred in both <AmE> and <BrE>. However, a different construction is often a more natural choice, for example:
Did he smoke when you first knew him?
Dare and need can be constructed
as modal auxiliaries (with bare infinitive and without the inflected forms) or
as main verbs (with to-infinitive, -s inflection and past forms).
The modal auxiliary construction is mainly restricted to negative and interrogative sentences, whereas the main verb construction can always be used and is in fact the more common.
Dare and need as auxiliaries are probably rarer in <AmE> than in <BrE>.
NEED, DARE Modal Auxiliary Main Verb
positive - He needs to go now.
He dares to go now.
negative He needn't go now. He doesn't need to go now.
He daren't go now. He doesn't dare to go now.
interrogative Need he go now? Does he need to go now?
Dare he go now? Does he dare to go now?
negative-interrogative Needn't he go yet? Doesn't he need to go yet?
Daren't he go yet? Doesn't he dare to go yet?
Note
[a] The modal auxiliary construction is not confined to negative and/or interrogative sentences but can also occur in other contexts with similar meanings, for example,
He need do it only under these circumstances.
He need do it but once.
He need have no fear.
No soldier dare disobey.
Nobody would dare predict.....
All you need do is ... (`You need do no more than...')
DARE -
A mixture of the two constructions is sometimes found in the case of dare, which may have the do-construction with a bare infinitive: We did not dare speak...
DARE is also unique in that we can say: I didn't dare to / I daren't / I dared not mention it to him yesterday.