CAN (OFFER)

Used in polite offers of help
Can I help you with those bags?
I'm afraid Ms Ferguson has already left the office. Can I be of any help?

EXTRA EXAMPLES

Is there anything I can do to help?

You can go instead of me, if you want.

You look lost - can I help you?

What a lot of bags! Can I carry something for you?

"If you like I can do some shopping for you." "That's a very kind offer."

CAN (POSSIBILITY)

Used to express possibility
You can get stamps from the local newsagents.
You can get very nasty skin diseases from bathing in dirty water.
Smoking can cause cancer.
Noise can be quite a problem when you're living in a flat.
He can be really annoying at times (= He is sometimes very annoying).

EXTRA EXAMPLES

Couples who are childless can feel excluded from the rest of society.

Children can choke on peanuts.

Clearance of a cheque can take up to a week.

You can get travel concessions if you are under 26.

Not making a will can have serious consequences for the people you might wish to benefit.

CAN (REQUEST)

Used to request something
If you see Adrian, can you tell him I'm in London next weekend?
Can you make a little less noise, please? I'm trying to work.

EXTRA EXAMPLES

I can't get the cork out of the bottle - can you try?

Excuse me, can I just get past?

It's freezing in here - can I close the window?

Please can I have a go on your bike?

Andrew, can you help me install this software?

CAN (PERMISSION)

T be allowed to
Can I use your bike, John?
You can park over there.
You can have a piece of cake after you've eaten your vegetables!

EXTRA EXAMPLES

If you finish early you can go home.

She can come whenever she likes, as far as I'm concerned.

Finish up your dinner and you can have dessert.

How early can you get off this afternoon?

Anyone can go - you don't have to be invited.

Usage Notes

can, could or may?

Can is used in standard spoken English when asking for permission. Could is slightly more formal. Both of these are acceptable in most forms of written English, although in very formal writing, such as official instructions, may is usually used instead.

Persons under 14 unaccompanied by an adult may not enter.

CAN (ABILITY)

To be able to
Can you drive?
She can speak four languages.
Can you read that sign from this distance?
The doctors are doing all that they can, but she's still not breathing properly.
Do the best you can - I realize the circumstances are not ideal.
If the party is awful, we can always leave (= that would be one possible solution to our problem).
"She's really furious about it." "Can you blame her (= I'm not surprised)?"

EXTRA EXAMPLES

I don't know how he can afford a new car on his salary.

Cats can see in the dark.

The water's not deep here - look, I can touch the bottom.

I doubt whether I can finish the work on time.

Computers can perform millions of calculations every second.

COMMON LERNER ERROR

can/could or be able to?

Be able to means the same as can, but it is used in different kinds of sentences. Be able to is used after modal and auxiliary verbs, for example when you use the verb will in order to talk about the future.

I'm afraid I won't be able to come to your party.

I'm afraid I won't can come to your party. (wrong)

When you form the simple past with could it refers to a general ability.

I could swim before I was three.

When you form the simple past with was/were able to it refers to something you managed to do on a particular occasion.

A man was able to swim out to the girl and save her.