Download They are can, could, may, might, will, would, shall, should, must

Auxiliaries
English verbs, in terms of their functions in
forming verb phrases, fall into two major
categories: main verbs and auxiliaries.
Auxiliaries can again be divided into primary
auxiliaries, modal auxiliaries, and semi-auxiliaries.
• The function of primary auxiliaries (be, do,
have) is to combine with main verbs to form
complex verb phrases.
• The present lecture will concentrate on the
use of modal auxiliaries and semi-auxiliaries.
• It is generally acknowledged that English has 13
modal auxiliaries (or "modals" for short). They
are can, could, may, might, will, would, shall,
should, must, ought to, dare, need, used to.
• Morphologically, modals have no non-finite forms,
nor -s form for third person singular present tense.
• Syntactically, modals can only be the initial
element of a finite verb phrase and are invariably
followed by a bare infinitive.
• In terms of semantics, modals have lexical
meanings and no two modals can co-occur in a
verb phrase.
• The tense distinctions of modals are not the
chief markers of time reference, that is to say,
their present forms do not necessarily refer to
present time, nor do their past forms to the
past.
• What is more, most modals are polysemous,
and they behave differently in affirmative,
negative, and interrogative sentences.
• Here is a survey of the uses of the modals.
1 Modals and modal meanings
（1） Ability and possibility
The modals used in these senses are can,
could, may, might and be able to.
（a） To talk about "ability", we can use
can, could, and be able to.
（b） To talk about "possibility", we can use
may, might, can and could.
He may not go tomorrow. (prohibition)
He may not go tomorrow. (impossibility)
• She can't / could have missed the train.
• Note that "might / could have + -ed" is
sometimes used to talk about an unrealized
possibility in the past, about something that
was possible but did not happen, e.g.
• You might have finished the work last week,
but you didn't.
（2） Permission, and prohibition
The modals used in these senses are can, could,
may and might.
（a） To ask for permission, we can use can, could,
may, might. Compared with can / could, may / might
sounds more formal; compared with can / may, the
past forms sound more polite, implying no
difference in time reference. In colloquial English,
can is very frequently used to ask for permission,
e.g.
Can I smoke in here?
（b） To refuse to give permission, we can use
may not (with stress on not) or cannot, e.g.
Can I go out for a moment?
No, you can't.
May I use your car for a few days?
No, you may not.
• In impersonal statements, may not can also be used
to indicate what is not permitted by rules or
regulations, e.g.
Borrowers may not take out of the library more than
two books at a time.
Note that the past form of may not (in the sense of
refusal to give permission) is not might not. The
notion of refusing to give permission in the past is
usually expressed by other forms, e.g..
He was not allowed to go.
I didn't permit him to go.
（3） Obligation and necessity
The modals used in these senses are should,
ought to, must and have to / have got to.
（a） To talk about "obligation", we can use
should, ought to and must. Used in this sense,
these three modals vary slightly in tone.
Should and ought to are used to advise or
urge. These two modals are interchangeable
in most cases. There is, however, a very
slight difference: Should is used when we
give our own subjective opinion; ought to
has a rather more objective force.
Consequently, should, rather than ought to,
is used to give strong advice, e.g.
You should / ought to have asked my
permission first.
Must is even stronger than should. Used
in the sense of "obligation", must usually
implies that the speaker is the person in
authority :
You must be back by ten o'clock.
Need not / needn't denotes absence of
obligation or necessity. Alternative forms of
needn't are "don't need to", "don't have to",
and "haven't got to" with corresponding
past forms "didn't need to" and "didn't
have to", e.g..
A: Must you leave so soon?
B: No, I needn't.
He didn't need to do it at once.
（b） Should and ought to can be used to denote
assumptions arrived at by inference, not by direct
experience, e.g.
That should not be a difficult problem for Mary.
These young trees ought to provide shade in ten
years.
Ought to in this sense is synonymous with must
denoting "necessity", only it sounds less certain
than must, e.g..Bob must be home by now.
Bob ought to be home by now.
(4) Prediction and predictability
The modals used in these senses are will,
shall, would, should, ought to and must.
(a) The shall/ will future can be used for
predicting.
(b) The modals relating to predictability or
assumption are will and would apart from
should, ought to and must. Predictability
denoted by will and would can be classified
into specific predictability, habitual
predictability and timeless predictability.
(5) Willingness, intention and determination
The modals used in these senses are will, would
and shall.
(a) Will in the meaning of willingness or weak
volition is found with subjects of all three persons.
Will so used is normally unstressed and can be
contracted to 'll, e.g.
I will / I'll lend you the money if you need it.
Who will / Who'll go with me?
(b) Another type of weak volition is intention
that can be expressed by will in all persons.
Will in this sense is unstressed and is
generally contracted to 'll, e.g.
I'll get some drinks. What’ll you have?
He won't help me unless I accept his offer.
(c) Determination or insistence, also referred to as
strong volition, is expressed by stressed will, which
cannot be contracted to 'll. Stressed will can be
used in all persons, e.g.:
•
I will ( = am determined to) take the job and no
one is going to stop me.
•
If you'll eat ( = insist on eating) too much pastry,
you can't complain if you get fat.
•
He'll go out ( = insists on going out) without an
overcoat although the weather is so cold.
(6) Other modal meanings
The modals dealt with here are should,
would, dare, need and used to.
(a) In specific contexts, should can denote
emotional feelings of sorrow, joy, displeasure,
surprise, wonder, etc. Should in this sense is
especially common in certain that-clauses,
in rhetorical questions and in some
idiomatic exclamations, e.g. .
• It's unbelievable that he should have
finished the work so soon.
• How should I know?
• That he should dare to attack me!
• In some other contexts, should can function as
a substitute for be-subjunctive, in which case
should is without any definite modal meaning,
e.g.
I insisted that he go / should go with me.
• This use of should is also found in adverbial
clauses introduced by for fear that, so that, and
lest ( = for fear that), e.g.
He ran away lest he should be found by people.
(b) Would can be used to make a tactful
statement, a polite request, and a tentative
suggestion, e.g.
It would be a shame to stop our work
halfway.
Would you like to stay here for the night?
Wouldn't it be better for us to start off a little
earlier tomorrow morning?
(c) As a modal, dare (except in "I dare say") is
restricted to questions and negative statements.
Modal dare has no past form. It may appear in
present time as well as in past time contexts.
Likewise, daren't, the negative form of dare,
too, can be used for both present and past time
reference, e.g.:
I dare not go there.
How dare he say such rude things about me?
(d) Need can also be used as a modal or as a
main verb. As a modal, need only occurs in
questions and negative statements. Note that
in answer to a question introduced by need,
we should use must in a positive response
and needn't in a negative response, e.g.
Need we work late today?
No, we needn't, but we must tomorrow.
(e) Used to is commonly used to denote a past habitual
action or an existence in the past. The use of this
modal stresses the notion that the habit has been
given up or the state no longer exists. The negative
form of used to is usedn't to, e.g.:
He used to live in Shanghai, usedn't he?
• In negative statements and negative questions, we
may either use "didn't use to" or "usedn't to", e.g.:
•
He didn't use to smoke cigarettes.
= He usedn't to smoke cigarettes.
2 Epistemic and non-epistemic use of
modals
As has been pointed out, modals are mostly
polysemous. In terms of the meanings they express,
modals can be divided into two categories—epistemic
and non-epistemic. The function of epistemic modals is
to make judgments about the possibility or necessity
that something is or is not the case. The non-epistemic
category only describes the fact as it is, e.g.
•
He must be very careless. (epistemic)
•
We must be careful. (non-epistemic)
(1) Epistemic modals
• As the examples demonstrate, there are nine modals that
have both epistemic and non-epistemic functions. A
summary below will help to illustrate this..
• modals
non-epistemic use
epistemic use
• can / could
ability, permission possibility
• may / might
permission
possibility
• will / would
volition
predictability
• should / ought to obligation logical necessity
• must
obligation
logical necessity
• In their epistemic uses, the above modals can be arranged on a
scale according to the degree of certainty or uncertainty that the
speaker feels. Might can be viewed as the most uncertain, while
must as the most certain. The scale is as follows:
• uncertain
might
That might be George.
•
may
•
could
•
can
•
should
•
ought to
•
would
•
will
• certain
must
That must be George.
• From the scale above we can see that might, may, could,
can refer to "possibility"; should, ought to, would, will
to "probability" must to "certainty". The past forms
of epistemic modals are realized by adding a perfective
infinitive, e.g.:
•
That might have been George.
•
That must have been George.
• Note that the negative equivalent of must is can't, e.g.
•
That can't be George.
•
That can't have been George.
(2) Syntactic features of epistemic
modals
• The following five syntactic features are
common to all epistemic modals;
• (a) All epistemic modals can combine with a
perfective infinitive, e.g.:
•
You must have been disappointed.
(b) All epistemic modals can combine with a
progressive infinitive, e.g.:
• He must be working late at the office.
• He must have been working late at the office.
(c) All epistemic modals can be used in
existential sentences, e.g.:
• There must be some mistake.
(d) All epistemic modals can combine with
sativa verbs, e.g.:
•
He must understand that we mean
business
(e) All epistemic modals can be used with an
inanimate subject, e.g.
It must be George.
Not all these features are shared by nonepistemic modals.
(3) Time reference of epistemic modals
• . About time reference of epistemic modals, there
are two points worth noting. First, in direct speech,
the modal statement is invariably made with
present time reference, because judgments or
deductions are usually made at the moment of
speaking, e.g.:
He might have lost his way.
He couldn’t be still working at the office.
• Secondly, the time reference of the contents of the
judgment or deduction is determined by the form of
the infinitive that follows the modal. When the
infinitive is in the simple or progressive form, it
usually refers to present or future time; if the
infinitive takes the perfective form, it refers to past
time, e.g.:
• He must be calling tonight.
= I'm sure he is calling tonight.
He may have come last year.
= It is possible that he came last year.
3 Semi-auxiliaries
Semi-auxiliaries constitute a category
of verbs between auxiliaries proper and
main verbs.
(1) Types of semi-auxiliaries
• Structurally, semi-auxiliaries fall into three
types: one type is initiated with the verb be; a
second type is initiated with the verb have; the
third type is initiated with the verb seem,
chance, happen, appear, etc.
• Most of the semi-auxiliaries belong to Subclass I. They
include:
be about to
be able to
be apt to
be bound to
be due to
be going to
be liable to
be obliged to
be supposed to
be sure to
be to
be willing to
had better
had best
have to
have got to
come to
fail to
get to
tend to, etc
• The following semi-auxiliaries belong to
Subclass II:
be certain to
happen to
be (un)likely to
seem to
appear to
turn out to
chance to, etc
• Semi-auxiliaries are invariably followed by
infinitive which might be in the simple,
progressive or perfective form, e.g.:
•
I chanced to be out when he called.
•
He seems to be enjoying himself.
(2) Semi-auxiliaries and "it ... that-clause"
•
As has been said before, semi-auxiliaries of
Subclass II can be transformed into an "it ... thatclause" construction. The transformational
relation is more or less the same as when we
discussed the two passive possibilities. For
convenience sake, we might as well label the "it ...
that-clause" construction as Pattern I, and the
sentence with a semi-auxiliary as Pattern II, e.g.
• It appears that he has many friends in China.
(Pattern I )
•
He appears to have many friends in China.
(Pattern II )
Contracted forms of auxiliaries
• All the primary and modal auxiliaries have
contracted forms, which may be divided
into two types: negative contractions and
positive contractions.
(1) Negative contractions
•
All the primary and modal auxiliaries except "am
not" have negative contractions:
am not
don't
couldn't
aren't
doesn't
mayn't
isn't
didn't
mightn't
wasn't
shan't
mustn't
weren't
won't
oughtn't
haven't
shouldn't
needn't
hasn't
wouldn't
daren't
hadn't
can't
usedn't
• The negative contractions of the verb be
may take two forms, except for the first
person singular..
I'm not
--(aren't)
he's / she's / it's not
he/she/it isn't
(wasn't)
we're / you're / they're not we/you/they
aren't (weren't)
(2) Positive contractions
• There are only ten items that have positive contractions.
These include: am ('m), is ('s), are ('re), have ('ve), has
('s), had ('d), shall ('II), will ('II) ; should ('d), would ('d).
These positive contracted forms are usually combined
with personal pronouns, with noun phrases, with
possessive, demonstrative, and indefinite pronouns, with
introductory there, as well as with interrogative words,
e.g.
I 'd be grateful if you'd lend me your car.
Mary's coming tomorrow evening.
(3) Restrictions on the use of positive
contractions
• There are situations in which positive
contractions cannot be used.
(a) They cannot be used in short responses,
e.g.:
•
Have you finished your work?
•
Yes, I have. ( * I've)
(b) They do not appear at the end of a
sentence, e.g.
•
John is not such a good student as Bill is.
( * as Bill's)
(c) They do not occur in general questions, e.g.
•
Is it raining?
•
Yes, it is.
(d) They cannot be used when the verb is stressed,
e.g.
•
You're coming with me?
•
I am coming whether you like it or not.
(e) The verb have cannot be contracted when it is
used to denote "possession", nor can have to
when used to denote "obligation", e.g.:
•
They have three children. ( * They've)
•
He has to leave early. ( * He's to)
• This restriction, however, does not apply to
have got or have got to, e.g.:
They've got three children.
He's got to leave early.