Double Modal

The English modal verbs are a subset of the English auxiliary verbs used mostly to express modality (properties such as possibility, obligation, etc.). They can be distinguished from other verbs by their defectiveness (they do not have participle or infinitive forms) and by their neutralizationQuirk, Randolph, Sidney Greenbaum, Jan Svartvik, & Geoffrey Leech. 1985. A comprehensive grammar of the English language. London: Longman. (that they do not take the ending ''-(e)s'' in the third-person singular).

The principal English modal verbs are ''can'', ''could'', ''may'', ''might'', ''shall'', ''should'', ''will'', ''would'', and ''must''. Certain other verbs are sometimes classed as modals; these include ''ought'', ''had better'', and (in certain uses) ''dare'' and ''need''. Verbs which share only some of the characteristics of the principal modals are sometimes called "quasi-modals", "semi-modals", or "pseudo-modals".

Modal verbs and their features

The verbs customarily classed as modals in English have the following properties:
* They do not inflect (in the modern language) except insofar as some of them come in present–past (present– preterite) pairs. They do not add the ending ''-(e)s'' in the third-person singular (the present-tense modals therefore follow the preterite-present paradigm).
* They are defective: they are not used as infinitives or participles (except occasionally in non-standard English; see below), nor as imperatives, nor (in the standard way) as subjunctives.
* They function as auxiliary verbs: they modify the modality of another verb, which they govern. This verb generally appears as a bare infinitive, although in some definitions, a modal verb can also govern the ''to''-infinitive (as in the case of ''ought'').
* They have the syntactic properties associated with auxiliary verbs in English, principally that they can undergo subject–auxiliary inversion (in questions, for example) and can be negated by the appending of ''not'' after the verb.

The following verbs have all of the above properties, and can be classed as the principal modal verbs of English. They are listed here in present–preterite pairs where applicable:
* ''can'' and ''could''
* ''may'' and ''might''
* ''shall'' and ''should''
* ''will'' and ''would''
* ''must'' (no preterite; see etymology below)

Note that the preterite forms are not necessarily used to refer to past time, and in some cases, they are near-synonyms to the present forms. Note that most of these so-called preterite forms are most often used in the subjunctive mood in the present tense. The auxiliary verbs ''may'' and ''let'' are also used often in the subjunctive mood. Famous examples of these are "May The Force be with you." and "Let God bless you with good." These are both sentences that express some uncertainty; hence they are subjunctive sentences.

The verbs listed below mostly share the above features but with certain differences. They are sometimes, but not always, categorized as modal verbs. They may also be called "semi-modals".

* The verb ''ought'' differs from the principal modals only in that it governs a ''to''-infinitive rather than a bare infinitive (compare ''he should go'' with ''he ought to go'').
* The verbs ''dare'' and ''need'' can be used as modals, often in the negative (''Dare he fight?''; ''You dare not do that.''; ''You need not go.''), although they are more commonly found in constructions where they appear as ordinary inflected verbs (''He dares to fight''; ''You don't need to go''). There is also a dialect verb, nearly obsolete but sometimes heard in Appalachia and the Deep South of the United States: ''darest'', which means "dare not", as in "You darest do that."
* The verb ''had'' in the expression ''had better'' behaves like a modal verb, hence ''had better'' (considered as a compound verb) is sometimes classed as a modal or semi-modal.
* The verb ''used'' in the expression ''used to (do something)'' can behave as a modal, but is more often used with ''do''-support than with auxiliary-verb syntax: ''Did she used to do it?'' (or ''Did she use to do it?'') and ''She didn't used to do it'' (or ''She didn't use to do it'') are more common than ''Used she to do it?'' and ''She used not (usedn't) to do it''.

Other English auxiliaries appear in a variety of different forms and are not regarded as modal verbs. These are:
* ''be'', used as an auxiliary in passive voice and continuous aspect constructions; it follows auxiliary-verb syntax even when used as a copula, and in auxiliary-like formations such as ''be going to'', ''is to'' and ''be about to'';
* ''have'', used as an auxiliary in perfect aspect constructions, including the idiom ''have got (to)''; it is also used in ''have to'', which has modal meaning, but here (as when denoting possession) ''have'' only rarely follows auxiliary-verb syntax (see also ' below);
* ''do''; see ''do''-support.

For more general information about English verb inflection and auxiliary usage, see English verbs and English clause syntax. For details of the uses of the particular modals, see below.

Etymology

The modals ''can'' and ''could'' are from Old English ''can(n)'' and ''cuþ'', which were respectively present and preterite forms of the verb '' cunnan'' ("to be able"). The silent ''l'' in the spelling of ''could'' results from analogy with ''would'' and ''should''.

Similarly, ''may'' and ''might'' are from Old English ''mæg'' and ''meahte'', respectively present and preterite forms of ''magan'' ("may, to be able"); ''shall'' and ''should'' are from ''sceal'' and ''sceolde'', respectively present and preterite forms of '' sculan'' ("to owe, be obliged"); and ''will'' and ''would'' are from ''wille'' and ''wolde'', respectively present and preterite forms of ''willan'' ("to wish, want").

The aforementioned Old English verbs ''cunnan'', ''magan'', ''sculan'', and ''willan'' followed the preterite-present paradigm (or, in the case of ''willan'', a similar but irregular paradigm), which explains the absence of the ending ''-s'' in the third person on the present forms ''can'', ''may'', ''shall'', and ''will''. (The original Old English forms given above were first and third person singular forms; their descendant forms became generalized to all persons and numbers.)

The verb ''must'' comes from Old English ''moste'', part of the verb '' motan'' ("to be able to, be obliged to"). This was another preterite-present verb, of which ''moste'' was in fact the preterite (the present form ''mot'' gave rise to '' mote'', which was used as a modal verb in Early Modern English; but ''must'' has now lost its past connotations and has replaced ''mote''). Similarly, ''ought'' was originally a past form—it derives from ''ahte'', preterite of ''agan'' ("to own"), another Old English preterite-present verb, whose present tense form ''ah'' has also given the modern (regular) verb ''owe'' (and ''ought'' was formerly used as a past tense of ''owe'').

The verb ''dare'' also originates from a preterite-present verb, ''durran'' ("to dare"), specifically its present tense ''dear(r)'', although in its non-modal uses in Modern English it is conjugated regularly. However, ''need'' comes from the regular Old English verb ''neodian'' (meaning "to be necessary")—the alternative third person form ''need'' (in place of ''needs''), which has become the norm in modal uses, became common in the 16th century.

Syntax

A modal verb serves as an auxiliary to another verb, which appears in the infinitive form (the bare infinitive, or the ''to''-infinitive in the cases of ''ought'' and ''used'' as discussed above). Examples: ''You must escape''; ''This may be difficult''.

The verb governed by the modal may be another auxiliary (necessarily one that can appear in infinitive form—this includes ''be'' and ''have'', but not another modal, except in the non-standard cases described below under ). Hence a modal may introduce a chain (technically catena) of verb forms, in which the other auxiliaries express properties such as aspect and voice, as in ''He must have been given a new job''.

Modals can appear in tag questions and other elliptical sentences without the governed verb being expressed: ''...can he?''; ''I mustn't.''; ''Would they?''

Like other auxiliaries, modal verbs are negated by the addition of the word ''not'' after them. (The modification of meaning may not always correspond to simple negation, as in the case of ''must not''.) The modal word ''can'' combine with ''not'' forms the single word ''cannot''. Most of the modals have contracted negated forms in ''n't'' which are commonly used in informal English: ''can't'', ''mustn't'', ''won't'' (from ''will''), etc.

Again like other auxiliaries, modal verbs undergo inversion with their subject, in forming questions and in the other cases described in the article on subject–auxiliary inversion: ''Could you do this?''; ''On no account may you enter.'' When there is negation, the contraction with ''n't'' may undergo inversion as an auxiliary in its own right: ''Why can't I come in?'' (or: ''Why can I not come in?'').

More information on these topics can be found at English clause syntax.

Past forms

The preterite (past) forms given above (''could'', ''might'', ''should'', and ''would'', corresponding to ''can'', ''may'', ''shall'', and ''will'', respectively) do not always simply modify the meaning of the modal to give it past time reference. The only one regularly used as an ordinary past tense is ''could'', when referring to ability: ''I could swim'' may serve as a past form of ''I can swim''.

All the preterites are used as past equivalents for the corresponding present modals in indirect speech and similar clauses requiring the rules of sequence of tenses to be applied. For example, in 1960, it might have been said that ''People think that we will all be driving hovercars by the year 2000'', whereas at a later date it might be reported that ''In 1960, people thought we would all be driving hovercars by the year 2000.''

This "future-in-the-past" (also known as the past prospective, see: prospective) usage of ''would'' can also occur in independent sentences: ''I moved to Green Gables in 1930; I would live there for the next ten years.''

In many cases, in order to give modals past reference, they are used together with a "perfect infinitive", namely the auxiliary ''have'' and a past participle, as in ''I should have asked her''; ''You may have seen me''. Sometimes these expressions are limited in meaning; for example, ''must have'' can refer only to certainty, whereas past obligation is expressed by an alternative phrase such as ''had to'' (see below).

Conditional sentences

The preterite forms of modals are used in counterfactual conditional sentences, in the apodosis (''then''-clause). The modal ''would'' (sometimes ''should'' as a first-person alternative) is used to produce the conditional construction which is typically used in clauses of this type: ''If you loved me, you would support me.'' It can be replaced by ''could'' (meaning "would be able to") and ''might'' (meaning "would possibly") as appropriate.

When the clause has past time reference, the construction with the modal plus perfect infinitive (see above) is used: ''If they (had) wanted to do it, they would (could/might) have done it by now.'' (The ''would have done'' construction is called the conditional perfect.)

The protasis (''if''-clause) of such a sentence typically contains the past tense of a verb (or the past perfect construction, in the case of past time reference), without any modal. The modal ''could'' may be used here in its role as the past tense of ''can'' (''if I could speak French''). However all the modal preterites can be used in such clauses with certain types of hypothetical future reference: ''if I should lose'' or ''should I lose'' (equivalent to ''if I lose''); ''if you would/might/could stop doing that'' (usually used as a form of request).

Sentences with the verb ''wish'' (and expressions of wish using ''if only...'') follow similar patterns to the ''if''-clauses referred to above, when they have counterfactual present or past reference. When they express a desired event in the near future, the modal ''would'' is used: ''I wish you would visit me''; ''If only he would give me a sign.''

For more information see English conditional sentences and English subjunctive.

Replacements for defective forms

As noted above, English modal verbs are defective in that they do not have infinitive, participle, imperative, or (standard) subjunctive forms, and, in some cases, past forms. However in many cases there exist equivalent expressions that carry the same meaning as the modal, and can be used to supply the missing forms. In particular:
*The modals ''can'' and ''could'', in their meanings expressing ability, can be replaced by ''am/is/are able to'' and ''was/were able to''. Additional forms can thus be supplied: the infinitive ''(to) be able to'', the subjunctive and (rarely) imperative ''be able to'', and the participles ''being able to'' and ''been able to''.
*The modals ''may'' and ''might'', in their meanings expressing permission, can be replaced by ''am/is/are allowed to'' and ''was/were allowed to''.
*The modal ''must'' in most meanings can be replaced by ''have/has to''. This supplies the past and past participle form ''had to'', and other forms ''(to) have to'', ''having to''.
*''Will'' can be replaced by ''am/is/are going to''. This can supply the past and other forms: ''was/were going to'', ''(to) be going to'', ''being/been going to''.
*The modals ''should'' and ''ought to'' might be replaced by ''am/is/are supposed to'', thus supplying the forms ''was/were supposed to'', ''(to) be supposed to'', ''being/been supposed to''.

Contractions and reduced pronunciation

As already mentioned, most of the modals in combination with ''not'' form commonly used contractions: ''can't'', ''won't'', etc. Some of the modals also have contracted forms themselves:
* The verb ''will'' is often contracted to '' 'll''; the same contraction may also represent ''shall''.
* The verb ''would'' (or ''should'', when used as a first-person equivalent of ''would'') is often contracted to ''d''.
* The ''had'' of ''had better'' is also often contracted to ''d''. (The same contraction is also used for other cases of ''had'' as an auxiliary.)

Certain of the modals generally have a weak pronunciation when they are not stressed or otherwise prominent; for example, ''can'' is usually pronounced . The same applies to certain words following modals, particularly auxiliary ''have'': a combination like ''should have'' is normally reduced to or just "shoulda". Also ''ought to'' can become "oughta". See weak and strong forms in English.

Usage of specific verbs

''Can'' and ''could''

The modal verb ''can'' expresses possibility in a dynamic, deontic, or epistemic sense, that is, in terms of innate ability, permissibility, or possible circumstance. For example:
*''I can speak English'' means "I am able to speak English" or "I know how to speak English."
*''You can smoke here'' means "you may (are permitted to) smoke here" (in formal English ''may'' or ''might'' is sometimes considered more correct than ''can'' or ''could'' in these senses).
*''There can be strong rivalry between siblings'' means that such rivalry is possible.

The preterite form ''could'' is used as the past tense or conditional form of ''can'' in the above meanings (see above). It is also used to express possible circumstance: ''We could be in trouble here.'' It is preferable to use ''could'', ''may'' or ''might'' rather than ''can'' when expressing possible circumstance in a particular situation (as opposed to the general case, as in the "rivalry" example above, where ''can'' or ''may'' is used).

Both ''can'' and ''could'' can be used to make requests: ''Can/could you pass me the cheese?'' means "Please pass me the cheese" (where ''could'' indicates greater politeness).

It is common to use ''can'' with verbs of perception such as ''see'', ''hear'', etc., as in ''I can see a tree''. Aspectual distinctions can be made, such as ''I could see it'' (ongoing state) vs. ''I saw it'' (event). See ''can see''.

The use of ''could'' with the perfect infinitive expresses past ability or possibility, either in some counterfactual circumstance (''I could have told him if I had seen him''), or in some real circumstance where the act in question was not in fact realized: ''I could have told him yesterday'' (but in fact I didn't). The use of ''can'' with the perfect infinitive, ''can have...'', is a rarer alternative to ''may have...'' (for the negative see below).

The negation of ''can'' is the single word ''cannot'', only occasionally written separately as ''can not''. Though ''cannot'' is preferred (as ''can not'' is potentially ambiguous), its irregularity (all other uncontracted verbal negations use at least two words) sometimes causes those unfamiliar with the nuances of English spelling to use the separated form. Its contracted form is ''can't'' (pronounced in RP and some other dialects). The negation of ''could'' is the regular ''could not'', contracted to ''couldn't''.

The negative forms reverse the meaning of the modal (to express inability, impermissibility or impossibility). This differs from the case with ''may'' or ''might'' used to express possibility: ''it can't be true'' has a different meaning than ''it may not be true''. Thus ''can't'' (or ''cannot'') is often used to express disbelief in the possibility of something, as ''must'' expresses belief in the certainty of something. When the circumstance in question refers to the past, the form with the perfect infinitive is used: ''he can't (cannot) have done it'' means "I believe it impossible that he did it" (compare ''he must have done it'').

Occasionally ''not'' is applied to the infinitive rather than to the modal (stress would then be applied to make the meaning clear): ''I could not do that, but I'm going to do it anyway.''

''May'' and ''might''

The verb ''may'' expresses possibility in either an epistemic or deontic sense, that is, in terms of possible circumstance or permissibility. For example:
*''The mouse may be dead'' means that it is possible that the mouse is dead.
*''You may leave the room'' means that the listener is permitted to leave the room.
In expressing possible circumstance, ''may'' can have future as well as present reference (''he may arrive'' means that it is possible that he will arrive; ''I may go to the mall'' means that I am considering going to the mall).

The preterite form ''might'' is used as a synonym for ''may'' when expressing possible circumstance (as can ''could'' – see above). It is sometimes said that ''might'' and ''could'' express a greater degree of doubt than ''may''. For uses of ''might'' in conditional sentences, and as a past equivalent to ''may'' in such contexts as indirect speech, see above.

''May'' (or ''might'') can also express irrelevance in spite of certain or likely truth: ''He may be taller than I am, but he is certainly not stronger'' could mean "While it is (or may be) true that he is taller than I am, that does not make a difference, as he is certainly not stronger."

''May'' can indicate presently given permission for present or future actions: ''You may go now''. ''Might'' used in this way is milder: ''You might go now if you feel like it.'' Similarly ''May I use your phone?'' is a request for permission (''might'' would be more hesitant or polite).

A less common use of ''may'' is to express wishes, as in ''May you live long and happy'' or ''May the Force be with you'' (see also English subjunctive).

When used with the perfect infinitive, ''may have'' indicates uncertainty about a past circumstance, whereas ''might have'' can have that meaning, but it can also refer to possibilities that did not occur but could have in other circumstances (see also conditional sentences above).
* ''She may have eaten the cake'' (the speaker does not know whether she ate cake).
* ''She might have eaten cake'' (this means either the same as the above, or else means that she did not eat cake but that it was or would have been possible for her to eat cake).

Note that the above perfect forms refer to possibility, not permission (although the second sense of ''might have'' might sometimes imply permission).

The negated form of ''may'' is ''may not''; this does not have a common contraction (''mayn't'' is obsolete). The negation of ''might'' is ''might not''; this is sometimes contracted to ''mightn't'', mostly in tag questions and in other questions expressing doubt (''Mightn't I come in if I took my boots off?'').

The meaning of the negated form depends on the usage of the modal. When possibility is indicated, the negation effectively applies to the main verb rather than the modal: ''That may/might not be'' means "That may/might not-be," i.e. "That may fail to be true." But when permission is being expressed, the negation applies to the modal or entire verb phrase: ''You may not go now'' means "You are not permitted to go now" (except in rare, spoken cases where ''not'' and the main verb are both stressed to indicate that they go together: ''You may go or not go, whichever you wish'').

''Shall'' and ''should''

The verb ''shall'' is used in some varieties of English in place of ''will'', indicating futurity when the subject is first person (''I shall, we shall'').

With second- and third-person subjects, ''shall'' indicates an order, command or prophecy: ''Cinderella, you shall go to the ball!'' It is often used in writing laws and specifications: ''Those convicted of violating this law shall be imprisoned for a term of not less than three years''; ''The electronics assembly shall be able to operate within a normal temperature range.''

''Shall'' is sometimes used in questions (in the first person) to ask for advice or confirmation of a suggestion: ''Shall I read now?''; ''What shall we wear?''

''Should'' is sometimes used as a first-person equivalent for ''would'' (in its conditional and "future-in-the-past" uses), in the same way that ''shall'' can replace ''will''. ''Should'' is also used to form a replacement for the present subjunctive in some varieties of English, and also in some conditional sentences with hypothetical future reference – see English subjunctive and English conditional sentences.

''Should'' is often used to describe an expected or recommended behavior or circumstance. It can be used to give advice or to describe normative behavior, though without such strong obligatory force as ''must'' or ''have to''. Thus ''You should never lie'' describes a social or ethical norm. It can also express what will happen according to theory or expectations: ''This should work.'' In these uses it is equivalent to ''ought to''.

Both ''shall'' and ''should'' can be used with the perfect infinitive (''shall/should have (done)'') in their role as first-person equivalents of ''will'' and ''would'' (thus to form future perfect or conditional perfect structures). Also ''shall have'' may express an order with perfect aspect (''you shall have finished your duties by nine o'clock''). When ''should'' is used in this way it usually expresses something which would have been expected, or normatively required, at some time in the past, but which did not in fact happen (or is not known to have happened): ''I should have done that yesterday'' ("it would have been expedient, or expected of me, to do that yesterday").

The formal negations are ''shall not'' and ''should not'', contracted to ''shan't'' and ''shouldn't''. The negation effectively applies to the main verb rather than the auxiliary: ''you should not do this'' implies not merely that there is no need to do this, but that there is a need not to do this. The logical negation of ''I should'' is ''I ought not to'' or ''I am not supposed to''.

''Will'' and ''would''

* ''Will'' as a tense marker is often used to express futurity (''The next meeting will be held on Thursday''). Since this is an expression of time rather than modality, constructions with ''will'' (or sometimes ''shall''; see above and at ''shall'' and ''will'') are often referred to as the future tense of English, and forms like ''will do'', ''will be doing'', ''will have done'' and ''will have been doing'' are often called the simple future, future progressive (or future continuous), future perfect, and future perfect progressive (continuous). With first-person subjects (''I'', ''we''), in varieties where ''shall'' is used for simple expression of futurity, the use of ''will'' indicates particular willingness or determination. (Future events are also sometimes referred to using the present tense (see Uses of English verb forms), or using the ''going to'' construction.)
* ''Will'' can express habitual aspect; for example, ''he will make mistakes'' may mean that he frequently makes mistakes (here the word ''will'' is usually stressed somewhat, and often expresses annoyance).
''Will'' also has these uses as a modal:Fleischman, Suzanne, ''The Future in Thought and Action'', Cambridge Univ. Press, 1982, pp. 86–97.Comrie, Bernard, ''Tense'', Cambridge Univ. Press, 1985, pp. 21, 47–48.
* It can express strong probability with present time reference, as in ''That will be John at the door''.
* It can be used to give an indirect order, as in ''You will do it right now''.

Modal uses of the preterite form ''would'' include:
* ''Would'' is used in some conditional sentences.
* Expression of politeness, as in ''I would like...'' (for "I want") and ''Would you (be so kind as to) do this?'' (for "Please do this").
As a tense marker ''would'' is used as
* Future of the past, as in ''I knew I would graduate two years later''. This is a past form of future ''will'' as described above under . (It is sometimes replaced by ''should'' in the first person in the same way that ''will'' is replaced by ''shall''.)

As an aspect marker, ''would'' is used for
* Expression of habitual aspect in past time, as in ''Back then, I would eat early and would walk to school.''

Both ''will'' and ''would'' can be used with the perfect infinitive (''will have'', ''would have''), either to form the future perfect and conditional perfect forms already referred to, or to express perfect aspect in their other meanings (e.g. ''there will have been an arrest order'', expressing strong probability).

The negated forms are ''will not'' (often contracted to ''won't'') and ''would not'' (often contracted to ''wouldn't''). In the modal meanings of ''will'' the negation is effectively applied to the main verb phrase and not to the modality (e.g. when expressing an order, ''you will not do it'' expresses an order not to do it, rather than just the absence of an order to do it). For contracted forms of ''will'' and ''would'' themselves, see above.

''Must''

The modal ''must'' expresses obligation or necessity: ''You must use this form''; ''We must try to escape''. It can also express a conclusion reached by indirect evidence (e.g. ''Sue must be at home'').

An alternative to ''must'' is the expression ''have to'' or ''has to'' depending on the pronoun (in the present tense sometimes ''have got to''), which is often more idiomatic in informal English when referring to obligation. This also provides other forms in which ''must'' is defective (see above) and enables simple negation (see below).

When used with the perfect infinitive (i.e. with ''have'' and the past participle), ''must'' has only an epistemic flavor: ''Sue must have left'' means that the speaker concludes that Sue has left. To express obligation or necessity in the past, ''had to'' or some other synonym must be used.

The formal negation of ''must'' is ''must not'' (contracted to ''mustn't''). However the negation effectively applies to the main verb, not the modality: ''You must not do this'' means that you are required not to do this, not just that you are not required to do this. To express the lack of requirement or obligation, the negative of ''have to'' or ''need'' (see below) can be used: ''You don't have to do this''; ''You needn't do this''.

The above negative forms are not usually used in the sense of a factual conclusion; here it is common to use ''can't'' to express confidence that something is not the case (as in ''It can't be here'' or, with the perfect, ''Sue can't have left'').

''Mustn't'' can nonetheless be used as a simple negative of ''must'' in tag questions and other questions expressing doubt: ''We must do it, mustn't we? Mustn't he be in the operating room by this stage?''

''Ought to'' and ''had better''

''Ought'' is used with meanings similar to those of ''should'' expressing expectation or requirement. The principal grammatical difference is that ''ought'' is used with the ''to''-infinitive rather than the bare infinitive, hence ''we should go'' is equivalent to ''we ought to go''. Because of this difference of syntax, ''ought'' is sometimes excluded from the class of modal verbs, or is classed as a semi-modal.

The reduced pronunciation of ''ought to'' (see above) is sometimes given the eye dialect spelling ''oughtta''.

''Ought'' can be used with perfect infinitives in the same way as ''should'' (but again with the insertion of ''to''): ''you ought to have done that earlier''.

The grammatically negated form is ''ought not'' or ''oughtn't'', equivalent in meaning to ''shouldn't'' (but again used with ''to'').

The expression ''had better'' has similar meaning to ''should'' and ''ought'' when expressing recommended or expedient behavior: ''I had better get down to work'' (it can also be used to give instructions with the implication of a threat: ''you had better give me the money or else''). The ''had'' of this expression is similar to a modal: it governs the bare infinitive, it is defective in that it is not replaceable by any other form of the verb ''have'', and it behaves syntactically as an auxiliary verb. For this reason the expression ''had better'', considered as a kind of compound verb, is sometimes classed along with the modals or as a semi-modal.

The ''had'' of ''had better'' can be contracted to '' 'd'', or in some informal usage (especially American) can be omitted. The expression can be used with a perfect infinitive: ''you'd better have finished that report by tomorrow''. There is a negative form ''hadn't better'', used mainly in questions: ''Hadn't we better start now?'' It is more common for the infinitive to be negated by means of ''not'' after ''better'': ''You'd better not do that'' (meaning that you are strongly advised not to do that).

''Dare'' and ''need''

The verbs ''dare'' and ''need'' can be used both as modals and as ordinary conjugated (non-modal) verbs. As non-modal verbs they can take a ''to''-infinitive as their complement (''I dared to answer her''; ''He needs to clean that''), although ''dare'' may also take a bare infinitive (''He didn't dare go''). In their uses as modals they govern a bare infinitive, and are usually restricted to questions and negative sentences.

Examples of the modal use of ''dare'', followed by equivalents using non-modal ''dare,'' where appropriate:
*''Dare he do it?'' ("Does he dare to do it?")
*''I daren't'' (or ''dare not'' or ''dasn't'') ''try''. ("I don't dare to try")
*''How dare you!'' (idiomatic expression of outrage)
*''I dare say''. (another idiomatic expression, here exceptionally without negation or question syntax)

The modal use of ''need'' is close in meaning to ''must'' expressing necessity or obligation. The negated form ''need not'' (''needn't'') differs in meaning from ''must not'', however; it expresses lack of necessity, whereas ''must not'' expresses prohibition. Examples:
*''Need I continue?'' ("Do I need to continue? Must I continue?")
*''You needn't water the grass'' ("You don't have to water the grass"; compare the different meaning of ''You mustn't water...'')

Modal ''need'' can also be used with the perfect infinitive: ''Need I have done that?'' It is most commonly used here in the negative, to denote that something that was done was (from the present perspective) not in fact necessary: ''You needn't have left that tip''.

''Used to''

The verbal expression ''used to'' expresses past states or past habitual actions, usually with the implication that they are no longer so. It is followed by the infinitive (that is, the full expression consists of the verb ''used'' plus the ''to''-infinitive). Thus the statement ''I used to go to college'' means that the speaker formerly habitually went to college, and normally implies that this is no longer the case.

While ''used to'' does not express modality, it has some similarities with modal auxiliaries in that it is invariant and defective in form and can follow auxiliary-verb syntax: it is possible to form questions like ''Used he to come here?'' and negatives like ''He used not'' (rarely ''usedn't'') ''to come here''. More common, however, (though not the most formal style) is the syntax that treats ''used'' as a past tense of an ordinary verb, and forms questions and negatives using ''did'': ''Did he use(d) to come here? He didn't use(d) to come here''.

Note the difference in pronunciation between the ordinary verb ''use'' and its past form ''used'' (as in ''scissors are used to cut paper''), and the verb forms described here: .

The verbal use of ''used to'' should not be confused with the adjectival use of the same expression, meaning "familiar with", as in ''I am used to this'', ''we must get used to the cold''. When the adjectival form is followed by a verb, the gerund is used: ''I am used to going to college in the mornings''.

Deduction

In English, modal verbs as ''must, have to, have got to, can't'' and ''couldn't'' are used to express deduction and contention. These modal verbs state how sure the speaker is about something.

*You're shivering—you must be cold.
*Someone must have taken the key: it is not here.
*I didn't order ten books. This has to be a mistake.
*These aren't mine—they've got to be yours.
* It can't be a burglar. All the doors and windows are locked.

Double modals

In formal standard English usage, since modals are followed by a base verb, which modals are not, modal verbs cannot be used consecutively. That requirement then dictates they can be followed by only non-modal verbs. ''Might have to'' is acceptable ("have to" is not a modal verb), but ''*might must'' is not, even though ''must'' and ''have to'' can normally be used interchangeably. Two rules from different grammatical models supposedly disallow the construction. Proponents of Phrase structure grammar see the surface clause as allowing only one modal verb, while main verb analysis would dictate that modal verbs occur in finite forms.

A greater variety of double modals appears in some regional dialects. In English, for example, phrases such as ''would dare to'' and ''should have to'' are sometimes used in conversation and are grammatically correct. The double modal may sometimes be in the future tense, as in ''We must be able to work'' with ''must'' being the main auxiliary and ''be able to'' as the infinitive. Other examples include ''You may not dare to run'' or ''I would need to have help''.

To put double modals in past tense, only the first modal is changed as in ''I could ought to''. Double modals are also referred to as multiple modals.Kosur, Heather Marie. 2011. Structure and meaning of periphrastic modal verbs in modern American English: Multiple modals as single-unit constructions. Illinois State University. Department of English - Theses (Master's).

To form questions, the subject and the first verb are swapped if the verb requires no do-support, such as ''Will you be able to write?'' If the main auxiliary requires do-support, the appropriate form of ''to do'' is added to the beginning, as in ''Did he use to need to fight?'' If modals are put in the perfect tense, the past participle of the infinitive is used, as in ''He had been going to swim'' or ''You have not been able to skate''. In questions, the main verb and subject are swapped, as in ''Has she had to come?''

"I might could do something," for instance, is an example of a double modal construction that can be found in varieties of Southern American and Midland American English.

Comparison with other Germanic languages

Many English modals have cognates in other Germanic languages, albeit with different meanings in some cases. Unlike the English modals, however, these verbs are not generally defective; they can inflect, and have forms such as infinitives, participles and future tenses (for example using the auxiliary in German). Examples of such cognates include:
* In German: ; cognates of ''may'', ''must'', ''can'', ''shall'', and ''will''. Although German shares five modal verbs with English, their meanings are often quite different. does not mean "to be allowed" but "may" as epistemic modal and "to like" as a normal verb followed by a noun. It can be followed by an infinitive with the meaning of "to have a desire to". means "will" only in the sense of "to want to" and is not used to form the future tense, for which is used instead. , and are used similarly as English "must", "can", and "shall". Note, however, that the negation of is a literal one in German, not an inverse one as in English. This is to say that German ("I must") means "I need to", and (literally the same as "I must not") accordingly means "I don't need to." In English, "to have to" behaves the same way, whereas English "must" expresses an interdiction when negated. (need) is sometimes used like a modal verb, especially negated ( "He need not come.").
* In Dutch: ; cognates of ''may'', ''must'', ''can'', ''shall'', and ''will''.
* In Danish: , cognates of ''may/must'', ''can'', ''will'', ''shall''. They generally have the same corresponding meanings in English, with the exception of , which usually means "to want to" (but which can also mean "will").
* In Swedish: (past tense: ), , cognates of ''may/might'', ''must'', ''can'', ''will'', ''shall''. They generally have the same corresponding meanings in English, with the exception of , which means "to want to".

Since modal verbs in other Germanic languages are not defective, the problem of ''double modals'' (see above) does not arise: the second modal verb in such a construction simply takes the infinitive form, as would any non-modal verb in the same position. Compare the following translations of English "I want to be able to dance", all of which translate literally as "I want can dance" (except German, which translates as "I want dance can"):
* german: Ich will tanzen können.
* nl, Ik wil kunnen dansen.
* da, Jeg vil kunne danse.
* sv, Jag vill kunna dansa.

See also

*

Notes

References

External links

* Verbs in English Grammar, wikibook

modal auxiliaries
Website/Project that collects phrases containing modal auxiliaries on the web (in German and English)

modal auxiliaries
Website/Project that collects phrases containing modal auxiliaries on the web (in German and English)

''Modal auxiliary verbs: special points''

{{DEFAULTSORT:English Modal Verb
English modal and auxiliary verbs