"Could" and "be able to"

  1. Jane played well, but I could beat her.
  2. Jane played well, but I was able to beat her.

Could you tell me what the difference is between the two sentences?

  1. I found I could beat him.

Which does this sentence mean, “I found I had the capability to beat him, but I won’t tell you whether or not I actually beat him.” or “I found I had the capability to beat him, and I actually beat him.”?[/i]

1 & 2-- There is no difference where ‘could’ is used as the past tense of ‘can’. The problem is that ‘could’ is more often used in conditional sentences as an auxiliary of hypothesis, so it is preferable to use ‘was able to’ for past situations of ability.

3-- I found that I had the ability; it is presumed that this was discovered through actually doing so, though it is not stated.

I see! Those who use “was/were able to” for the past are those who favor clarity of meaning!
Thanks a lot, Mister Micawber!

The place was packed but fortunately we were able to get a table.

Can we use “could” in this sentence? Judging from your answer, we can’t–right?

You can, certainly, and most of us do-- but it takes the reader/listener just a moment to sort out which ‘could’ is meant. My argument is for style only-- not an argument for correctness.