Grammar › Can and could

Can and could: positive sentences

610 fill-in-the-gap exercises, 61 tests of ten

One form for every subject, then the plain verb. Could is the past of can, and also its polite form.

The pattern

Subject, modal, plain verb. Nothing agrees and nothing changes:

I can go. She can go. They can go.

Telling the three meanings apart

Context does all the work, and usually one reading is obviously right:

• I can lift it. — ability
• You can smoke outside. — permission
• It can rain for weeks here. — general possibility

be able to fills the gaps

Can has no infinitive and no perfect form, so be able to stands in wherever a modal cannot go:

• future: I will be able to help on Friday.
• perfect: She has been able to walk since the operation.
• after another verb: I’d like to be able to ski.

In the plain present, can is far more natural than am able to.

could as one possibility among several

When you are listing options, could is the usual form:

We could drive, or we could take the train.

That is not past and not polite — it is tentative.

All forms

Examples

Taken from the 610 sentences in this drill. The answer is highlighted.

• He plays in a band every Friday, and he can play the guitar really well.
• When I was younger, I could swim for hours.
• My dog is wonderfully quick, and he can catch a Frisbee in mid-air.
• In his school years, he could solve any math problem given to him.
• She teaches languages, so she can speak three of them fluently.
• They could help us with the project last week.
• My mom bakes every Sunday, and she can make delicious cakes.
• I miss my childhood when I could run and play without a care in the world.
• Dogs can hear sounds that humans cannot.
• By the end of the course, the children could swim in the deep end without help.
• Sarah can play the guitar very well now that she takes lessons.
• We could finish our project ahead of schedule if we put in extra effort.

Mistakes to avoid

Quick choices from this form

Other forms of Can and could