Can / Be Able ToListed below are examples and uses of can / could / be able to for ability and permission
|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.