A Student's Introduction to English Grammar

§3.1 Distinctive properties of auxiliary verbs 37

mentioned above). Nevertheless, subordinate subjunctives like [iii] are struc­

turally very like subordinate clauses with primary verb-forms: compare We insist

[that she brings her own fo od with her] (and, as we noted in §1.1 above, many

speakers use this instead of [iii]). The subordinate clauses in [iv-vi], however,

differ quite markedly in their structure from clauses with primary verb-forms. In

[iv] the clause is introduced by fo r rather than that, and the subject pronoun

appears in the form her rather than she. And in [v-vi] there is no subject.

3 Auxiliary verbs

We turn now to an important division within the category of verbs
between roughly a dozen auxiliary verbs and all the rest, which we call lexical
verbs. The auxiliary verbs (or more briefly, auxiliaries) differ sharply in gram­
matical behaviour from lexical verbs, and figure crucially in a number of
common constructions.
Within the auxiliaries there are also major differences between the special sub­
class known as modal auxiliaries and the rest of the class, which we will call
non-modal; the significance of the term 'modal' will be explained in §8, when
we consider the meanings expressed by these verbs. The classification is like
this:

[14] modal __

VERB

(miliary \

non-modal-

lexical _______ _

can, may, must, will, shall, ought, need, dare

be, have, do

allow, bring, come, drink, eat,find, go, hold,

invite ,jostle , know, learn, meet, navigate ...

The forms could, might, would, should are the preterite forms of the modals can,
may, will, and shall, respectively. They differ very considerably in their uses
from ordinary preterites, however, and thus may not at first appear to be
preterites (see §8.3).
We begin by looking at some of the most important grammatical properties dis­
tinguishing au xiliaries from lexical verbs. We then turn in §3.2 to the distinctive
properties of the modal auxiliaries. There is some overlap between auxiliary and
lexical verbs and in §3.3 we examine four such cases: need, dare, have and do.
Finally, §3.4 gives a general definition of auxiliary verb.

3.1 Distinctive properties of auxiliary verbs

Auxiliary verbs behave differently from lexical verbs in a number of ways.
The two most important ways involve subject-auxiliary inversion and negation.