modal verbs

Nine central modal auxiliary verbs are used to express modality: can, could, may, might, shall, should, will, would, must. These are invariant forms taking the role of auxiliary, they precede the negative particle not in negation and precede the subject in yes-no questions. They are followed in the verb phrase by a bare infinitive verb (e.g. can see, would go). In general, modals cannot co-occur with each other in the verb phrase; however, some regional dialects allow modals in series (such as might could or might should).Although the central modals form a homogeneous group, the boundary between modals and lexical verbs taking infinitive complementation is in some cases unclear.First, there is a handful of marginal auxiliary verbs (e.g. need (to), ought to, dare (to), used to). These verbs can behave like modals in taking auxiliary negation and yes-no question inversion (needn't, ought we to . . ., She dare not, etc.). However, such constructions are extremely rare and largely confined to BrE.In addition, there are a number of fixed idiomatic phrases with functions similar to those of modals: (had) better, have to, (have) got to, be supposed to, be going to. Note that in orthographic representations of the spoken language, better, gotta, and gonna often occur as reduced forms of had better, have got to, and be going to. A contraction of thepreceding auxiliary can also appear ('d better, 've gotta, 'm gonna), but this is frequently omitted with better and gotta.These expressions are called semi-modals. (Other terms used for these expressions are 'quasi-modals' and 'periphrastic modals'.) In the counts and discussions that follow we have included the three marginal auxiliaries other than dare as semi-modals.Unlike the central modal verbs, many of the semi-modals can be marked for tense and person, and can occur as non-finite forms. In the infinitive, they can sometimes co-occur with a central modal verb or another semi-modal:He had to call the police. (conv)I think the teachers are gonna have to be there. (conv)I know you have to protect your eyesight. (FICT)The county council will have to ask colleges to bid for money on its behalf.(NEWS)Maybe she need to grow up a bit more. ( conv )You might need to get back quick. (FICT)He needed to be sure that current arrangements were working as well as possible. (NEWS)Beyond this there are a large number of other relatively fixed expressions with meanings similar to the modal auxiliaries; for example, want to, be able to, be obliged to, be likely to, be willing to. These differfrom other semi-modals, however, in that the component parts contribute independently to the overall meaning of the phrase.The central modal verbs can be used to make time distinctions, even though they are not formally marked for tense. For example, the modals will and shall, and the semi-modal be going to, can be used to refer to future time:There will be no outcry from the corporate sector about the disarray in the accountancy profession. (NEWS)We shall deal with these questions in 4.4. (ACAD)It's going to be hot. (conv)In addition, it is possible to group the central modals (except for must) into pairs with related meanings. These can in limited circumstances be used to distinguish between past time and non-past time:Compare, for example, the following pairs:I think we can beat Glenavon. (NEWS)v. In 1971 he thought he could help his brother in his illness by writing about their childhood. (NEWS)You know he'll come. (conv)v. I knew I would put on weight. ( conv)The second example in each pair involves a backshifted time reference.However, there are a number of other meaning distinctions made by these pairs of modals, with the main functions relating to speaker stance rather than the marking of time distinctions. For example, modals associated with past time are also associated with hypothetical situations, conveying overtones of tentativenessand politeness:Could I sit here a minute, Joyce? (conv)Could you sign one of these too? Would you mind? (conv)For this reason, we regard modal verbs as unmarked for tense. Modals and semi-modals can be grouped into three major categories according to their main meanings (excluding used to, which relates to past time).●Permission/possibility/ability: can, could, may, might●Obligation/necessity:must, should, (had) better, have (got) to,need to, ought to, be supposed to●Volition/prediction: will, would, shall, be going to.Each modal can have two different types of meaning, which can be labeled intrinsic and extrinsic (also referred to as 'deontic' and 'epistemic'meanings). Intrinsic modality refers to actions and events that humans (or other agents) directly control: meanings relating to permission, obligation, or volition (or intention). Extrinsic modality refers to the logical status of events or states, usually relating to assessments of likelihood: possibility, necessity, or prediction.There are two typical structural correlates of modal verbs with intrinsic meanings: (a) the subject of the verb phrase usually refers to a human being (as agent of the main verb), and (b) the main verb is usually a dynamic verb, describing an activity or event that can be controlled. In contrast, modal verbs with extrinsic meanings usually occur withnon-human subjects and/or with main verbs having stative meanings. Intrinsic meanings:You can't mark without a scheme. You must make a scheme. (CONV) <obligation>We shall not attempt a detailed account of linguistic categories in this book, but will use as far as possible those which are well enoughknown . .. (ACADt)<intention>Extrinsic meanings:You must have thought that you must have so much time. (CONV)<necessity>But in other cases his decisions will seem more radical. (ACAD)<prediction>It should be noted, however, that these correlates are not absolute. For example, the modal might often occurs in an extrinsic sense (marking possibility rather than permission) with both an animate subject and dynamic main verb:Otherwise you might jeopardize the situation. (CONV)Or he might accept it but reach different conclusions. (ACAD) Each of the modals is discussed in more detail below, describing its use preferences with intrinsic or extrinsic meanings in different registers.。