But you should only use 'was/were able to' with action verbs to talk about an ability related to a single event or incident in the past. ... You can use either 'could' or 'was/were able to' with some stative verbs (see, hear, feel, taste) to discuss ability related to a single event or incident in the past.

Could was were able to ability?

We use could to talk about an ability somebody had in the past. We use was/were able to to talk about a specific event in the past.

Can be could be difference?

Can, like could and would, is used to ask a polite question, but can is only used to ask permission to do or say something ("Can I borrow your car?" "Can I get you something to drink?"). Could is the past tense of can, but it also has uses apart from that--and that is where the confusion lies.