Can

“Can” could show that something is possible, or that you are able to do something.
It is used when we talk about:
1) abilities (I can speak Spanish. He can drive. You can’t lift those boxes.),
2) request or permission (Can I come in? You can’t swim in the lake!),
3) probability – usually in the negative (That can’t be Jim, he is much taller.)
All these cases refer to the present.

If we want to talk about the future, instead of „can”, we use “be able to”:
I won’t be able to come.
In a few months I will be able to lift weights again.
Now that he broke his leg, will he be able to take part in the play?

For the past there are two possibilities: “could” and “was/were able to”. More about them – here.