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

Negative form contraction

Modal verbs are often used in contracted negative forms (sometimes causing a

change in the form of the verb). 

Uncontracted and contracted negative forms of modal verbs

modal verb

uncontracted negative

contracted negative

can

cannot

can’t

could

could not

couldn’t

may

may not

mayn’t 

(very rare)

might

might not

mightn’t

will

will not

’ll not, won’t

shall

shall not

’ll not, shan’t

would

would not

’d not, wouldn’t

should

should not

shouldn’t

must

must not

mustn’t

Û

387 Will and 390 Would

Û

539 Glossary for any unfamiliar terms

Modality | 641

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CAN

381

Uses

Can

is the most frequent modal verb. It has a number of meanings; its most

frequent uses are for permission and ability.

Permission

Can

is frequently used to seek permission, give permission or, in the negative, 

to forbid:

You 

can borrow the car but be careful.

Students 

can hand in essays at any time before midday on February 3rd.

A: Can I smoke in here? 

B: No, I’m sorry you can’t.

[adult to a very small child who has just picked up a glass]

No. You 

can’t have that. You might break it.

Ability

A very frequent use of can is to indicate ability. This is particularly so with verbs 

of perception such as hear and see and with mental process verbs such as follow

(in the sense of ‘understand’), guess, imagine, picture, understand:

You 

can hear the atmosphere in the stadium.

Can you see the post office on the corner?

I 

can guess what you’re thinking right now.

I 

can just imagine how surprised they looked.

Liz 

can work right through the night.

General truths

Can

is used in statements about events and states which are true or which are

usually the case:

Steel 

can resist very high temperatures.

It 

can rain quite a lot in Ireland in August.

Thai 

can be a very difficult language for Westerners to pronounce.

✪

Could

is not normally used for general or current truths with present time

reference:

The verb ‘help’ 

can be used with or without infinitive ‘to’.

(stating a fact about English grammar)

(The verb ‘help’ could be used with or without infinitive ‘to’.)

Tommy 

can be really irritating at times. I don’t think he realises.

(the speaker believes this is true)

(Tommy could be really irritating at times. I don’t think he realises.)

642 | Modality

Cambridge Grammar of English

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Could

is used in such contexts only in reference to past time:

Liam 

could be so stubborn, but at the end of the day, he was a good

colleague.

Û

382 for the use of could as the past tense of can

Possibility

Can

is used to indicate or assess logical possibilities:

How 

can they be there already? They only left ten minutes ago.

That 

can’t be right.