00 / Modal Verbs
Ability: 'can' and 'could'
Use 'can' to describe abilities in the present and 'could' to describe abilities in the past.
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01 / 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.
02 / 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).
03 / 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. |
04 / Examples
05 / 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.
06 / Practice
When I was five, I ___ ride a bike, but now I ride every day.
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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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Answer: can
Why: The word 'now' indicates a present ability.
___ you swim when you were a child?
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Answer: Could
Why: This is a question about an ability in the past ('when you were a child').