Abilities - can, could, be able to.

Can / Be Able To

Listed below are examples and uses of can / could / be able to for ability and permission

Examples	Usage
He can play tennis well. She is able to speak five languages. They can come on Friday. Jack will be able to come next week.	Use 'can' or 'be able to' to express an ability or possibility NOTE: The future of 'be able to' is 'will be able to
He could swim when he was five.	Could in the past means the general ability to do something.
They were able to get tickets for the concert. I was able to finish before 6. I couldn't come last night, sorry. OR I wasn't able to come last night, sorry.	IMPORTANT: If someone was in the position to do something, or managed to do something, we use 'was/were able to instead of 'could' In the negative,' wasn't able to' OR 'couldn't' are both correct.