Can, could and be able to
Ability in the present, past and future: I can swim, I could read at four, I'll be able to drive next year.
Not sure B1 is your level? Find out in 8–40 questions, no account needed.
Can is for ability in the present and could for general ability in the past. Can has no other forms, so for the future, the present perfect and after other verbs we use be able to. For one success in the past, we usually say was able to or managed to, not could.
Can and could
Time | Positive | Negative | Question |
|---|---|---|---|
present | I can swim. | I can't swim. | Can you swim? |
past | I could swim at five. | I couldn't swim. | Could you swim? |
- She can speak three languages.
- My grandmother could sew beautifully.
- I couldn't sleep last night. It was too hot.
Be able to: the forms can doesn't have
Can has no infinitive, no -ing form and no participle. Where we need one of these, we use be able to + verb.
Form | Example |
|---|---|
future | I'll be able to help you next week. |
present perfect | I haven't been able to call her. |
after a modal | You might be able to get a ticket. |
after a verb | I'd like to be able to speak Italian. |
- Incorrect: I will can drive after my test.
- Correct: I will be able to drive after my test.Can has no form after will. Use will be able to.
- Incorrect: I haven't could sleep for days.
- Correct: I haven't been able to sleep for days.The present perfect needs a participle, so use been able to.
- Incorrect: I want to can play the piano.
- Correct: I want to be able to play the piano.After want, use to be able to.
Can for the future
For an ability someone will have in the future, use will be able to. But for a decision or an arrangement made now, can about the future is normal.
- In a year you'll be able to read a newspaper in English.
- I can meet you tomorrow at ten. (I'm free then.)
- Can you come to the meeting on Friday?
Could or was able to?
Could describes a general ability in the past: something you were able to do at any time. For one particular situation where someone succeeded, use was able to or managed to.
- When I was young, I could run very fast. (In general.)
- The fire spread quickly, but everyone was able to get out. (That time, they succeeded.)
- We managed to find a parking space near the theatre.
- Incorrect: After three hours, the firefighters could put out the fire.
- Correct: After three hours, the firefighters were able to put out the fire.For one success on one occasion, use was able to or managed to.
Couldn't: general and one occasion
In the negative there is no difference. Couldn't and wasn't able to are both correct, for general ability and for one occasion.
- I couldn't find my keys this morning.
- I wasn't able to find my keys this morning.
Could is also fine for one occasion with verbs of the senses: We could see the sea from our room.
Questions and short answers
Questions with be able to follow the verb be or will.
- Were you able to fix the printer? Yes, I was.
- Will you be able to finish by Monday? I hope so.
- Have you been able to speak to the manager?
Can or be able to in the present?
In the present, can is much more common. Be able to is possible but sounds more formal.
- I can't hear you. The music is too loud.
- The new system is able to process a thousand orders an hour.
Practise this rule
Related rules
Where this rule sits
All B1 rulesModal verbs: all rules