Can Could Vs Was / Were able to
1. To talk about an ability in the present, we use “can” or “be able to”
I can / am able to speak 2 languages.
He can / is able to swim.
My brother isn't able to drive a car
2. However to talk about a general ability in the past, we use “could” or “was / were able to”.
I could / was able to run very fast.
I could / was able to jump so high.
3. If we talk about a specific success in the past, we should only use “was / were able to”.
Since the exam was difficult only a few students
/ were able to pass it. (managed to pass it)
Mozart ---- compose little pieces of music even when he was 5.
a) can *b) could *c) was able to d) is able to
We ---- reach to the top of the hill before it got dark yesterday.
(Specific success in the past)
a) can b) could *c) were able to d) aren't able to
There is no difference between them when used in a negative sentence.
Because of the great financial difficulties, John couldn't / wasn't able to
finish his university education.
4. We use “can” instead of “be able to” in passive forms.
This game --- (play) by 2 or more players.
*a) can be played
b) is able to be played