Ability: 'can' and 'could'

A1 Beginner

Use 'can' to describe abilities in the present and 'could' to describe abilities in the past.

Overview

The modal verbs can and could express ability. Can refers to general abilities or skills a person has now, while could refers to abilities a person had in the past.

Form

subject + can/could + base verb

These verbs are followed by the base form of the main verb without 'to'. They do not change for the third person singular (he/she/it).

Present vs. Past Ability

Use cannot or can't for present inability, and could not or couldn't for past inability.

Time	Affirmative	Negative
Present	I can swim.	I cannot (can't) swim.
Past	I could swim.	I could not (couldn't) swim.

Examples

Common mistakes

He cans play tennis.
He can play tennis.
Modal verbs do not take an 's' in the third person.
I can to drive a car.
I can drive a car.
Do not use 'to' after modal verbs.

Practice

When I was five, I ___ ride a bike, but now I ride every day.
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couldn't
Answer:couldn't
Why:The context refers to a lack of ability in the past ('when I was five').
She ___ speak Spanish very well now because she practices every day.
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can
Answer:can
Why:The word 'now' indicates a present ability.
___ you swim when you were a child?
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Could
Answer:Could
Why:This is a question about an ability in the past ('when you were a child').