Student or Learner
When somebody says I was able to go out last night does it necessarily mean the speaker did go out? Or only had the opportunity?
I'd like to give you some information from Practical English Usage(Michael Swan). On page 105 it says:
We use could for 'general ability' - to say that somebody could do something at any time, whenever he/she wanted.(Was/were able is also possible.)
She could read when she was four. (OR She was able to read...)
My father could speak ten languages.
We do not normally use could to say that somebody managed to do something on one occasion. Instead, we use was/were able, managed or succeeded (in...ing).
How many eggs were you able to get? (NOT ...could you get?)
I managed to find a really nice dress in the sale. (NOT I could find...)
After six hours' climbing, we succeeded in getting to the top of the mountain. (NOT we could get tothe top...)
So...juding from the underlined part, your example could be interpreted as both. It really depends on the context, I guess.
I'm not a native speaker of English, so please forgive me if I'm wrong.