can, could, be able to
Talking about ability in the present, past and future.
The rules
- Modals never take -s or "to": "she can speak".
- Past general ability uses "could": "I could swim at five".
- Future ability needs "be able to", modals have no future form: "won't be able to".
- One specific past achievement takes "was able to" or "managed to", not "could".
- Present perfect + ability: "has been able to".
- Ability questions invert the modal: "Can you hear me?"
- Negative ability: "can't" + base verb. Modals never take "do".
Examples
- She can speak three languages fluently.
- When I was five, I could already swim.
- I'd love to come, but I won't be able to make it on Friday.
- Despite the noise, I was able to finish the exam.
- He has never been able to walk.
- Can you hear me at the back of the room?
- I can't open the file.
Quick check
Pick an answer to see the rule behind it.
1.She _____ speak three languages fluently.
2.When I was five, I _____ already swim.
3.I'd love to come, but I _____ to make it on Friday.
4.Which sentence is correct?
5._____ you hear me at the back of the room?