MODAL AUXILIARY VERBS
= the speaker´s attitude toward the action or state indicated by the infinitive
= defective Vs because they are not inflected; followed by bare inf.;
cannot form imperative; do not have the infinitive form;
negative and interrogative forms without the auxiliary:
= full and contracted negative forms;
I CAN / COULD
CAN = ability, capability; CANNOT / CAN´T = inability, incapability
Periphrastic form expresses the future, the infinitive, other structures:
CAN
- physical ability:
- mental ability:
- asking permission:
- giving permission:
- with Vs with perception:
- possibility:
- reference to the past by CAN´T /COULD / COULD NOT + perfect inf.
- CAN/CAN´T + passive infinitive:
I MAY / MIGHT; periphrastic forms:
- permission:
- in questions MAY is more formal than CAN:
- MIGHT in more polite requests:
- MUSTN´T stronger prohibition than MAY NOT:
- possibility :
- MAY + present infinitive = about present or future happenings
- MAY/MIGHT + perfect infinitive = we guess about past happ.:
- MIGHT expresses reproach:
- MIGHT + perfect infinitive = the action was not carried out in the past:
- MAY as a subjunctive auxiliary (expresses wish):
I MUST expresses:
TO HAVE TO; TO BE OBLIGED TO; TO BE COMPELLED TO;
- inescapable obligation, duty or necessity:
- an absence of obligation by NEED NOT or DON´T HAVE TO:
- MUSTN´T is a strong way of forbidding to do sth.:
- MUST, HAVE TO, HAVE GOT TO = interchangeable:
- obligation comes from the speaker:
- stronger obligation for other persons:
- MUST in notices, documents, commands:
- MUST in pressing invitation and emphatic advice:
- deduction: MUST + present inf.; refer to the present:
- MUST + perfect inf.; deduction about the past:
SHALL expresses:
- volition (mostly for 1st sg.):
- in questions = obligation:
- in questions = suggestions:
- insistence, threat:
- in legal documents- in 2nd, 3rd person in contracts, treaties:
SHOULD
- in reported speech („I shall stay there longer“):
- in offers, suggestions, requests:
- escapable obligation, duty:
- probability:
- after if and in case = possibility:
- recommendations from an outside authority:
- subjective opinion connected with:
OUGHT TO = more objective force, talk about laws, duties, regulations
SHOULD/OUGHT TO+perf. inf.=the past; action wasn´t carried out:
- OUGHT TO + perfect inf. = probability in the past:
WILL expresses:
- prediction about the future:
- prediction about the present (=MUST for deduction):
- habitual predictive meaning in conditional:
- prediction in a way of giving orders:
- willingness to do sth.:
- intention to make promises or threats:
- to make requests or to give orders:
WILL+perfect inf.=logical deduction about the past(MUST+perf.inf):
WOULD = past form, in reported speech:
- to talk about past habits + characteristic behaviour (never with state V):
- as conditional:
- more polite request than WILL:
- after I wish / If only I ... expresses willingness:
MARGINAL MODALS / SEMI-MODALS
NEED
= in the negative;
- in Yes/No questions:
- after negative adverbs (hardly, seldom, scarcely, rarely):
- in formal style, expressing doubts:
- in informal use = ordinary (lexical) V form:
NEEDN´T + perfect inf.= sb did it but it was not necessary:
Compare:
DARE:
- in questions
- in negatives:
- with bare inf.:
- with a full V:
- in informal style:
the negative DAREN´T:
YOU DARE! or: DON´T YOU DARE! = to discourage people from doing
- I DARE SAY = probably:
USED TO
=PAST habit = only in the simple past form:
also with state V:
- USED NOT or USEDN´T:
= in the negative;
= in questions:
However, DID is more common in the negative or in questions: