Cambridge Grammar of English Hardback with cd-rom a comprehensive Guide

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539 Glossary for any unfamiliar terms

Modality | 639

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It 

might have got lost in the post.

A: We can stick these in the letterbox tonight.

B: We could do, yeah.

(followed by substitute do)

✪

Modal verbs cannot be used as lexical verbs:

I 

must go to bed.

(I must to bed.)

I 

can speak Italian.

(or: I know Italian.)

(Not: I can Italian.)

Modal verbs can only stand alone when the lexical verb is understood:

A: Karen might have his number. 

B: Yes, she might.

(understood: she might have his number)

Modal verbs cannot indicate voice or aspect, though they may precede

constructions with passive voice and/or progressive/perfect aspect:

I think Jim 

could 

have been

offended.

I don’t know when we

’ll 

be arriving

yet.

We 

should 

have thought

of that earlier.

He 

might 

have been expecting

it.

Modal verbs and tenses

380b

Some of the core modal verbs historically represent present and past tense forms

which are no longer in one-to-one contrast as tenses.

Historical tense forms of modal verbs

historical present tense forms

historical past tense forms

can

could

may

might

shall

should

will

would

The historical present tense forms are not used to refer to the past; however, all 

of the forms may refer to either present or future time. In general, the historical

past tense forms are used to express greater tentativeness, distance and 

politeness.

640 | Modality

Cambridge Grammar of English

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