"Could you...?" vs. "Were you able to...?"

Question

I understand the difference in use between 'could' and 'was/were able to' to refer to a specific achievement.

I was able to attend the meeting yesterday.

He actually attended the meeting.

I could attend the meeting yesterday.

He had the possibility to attend, but we don't know whether he did or he didn't.

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Now, my question is as follows: do the same rules apply when we ask a question?

Were you able to attend the meeting yesterday?

Am I asking whether he attended or not?

Could you attend the meeting yesterday?

Am I asking the exact same thing as in the sentence above? Or am I simply asking whether he had the possibility to go, whether the possibility existed?

Answer 1

Well, it's really, really simple. Look at the two sentences. 1) I could run much faster when I was younger. 2) I was able to run much faster when I was younger. There's no difference in meaning between these two sentences. But when you use present perfect tense, you need to use a form of 'be able to,'because there's no form of 'can' or 'could' which you can use. For example:1) He has been able to swim since he was two years old (there's no way to use can or could in this sentence and keep the same meaning) 2) I like being to choose my own working hours(after like we need a verb with -ing, so we need to use be able to-there's no way to use can or could)

Answer 2

Were you able to attend the meeting yesterday?

Is used as the standard question.

Could you...

Tends to be used for things that are going to happen in the future, for example

Could you attend the meeting next week?

However I don't believe there are any strict rules governing what combinations of "could" or "was/were able to" you are allowed to use.