What is the difference among "can do", "could do" and "could have done"?
"Can do" means that it is currently possible to do something.
"Could do" means that it was once possible to do something, but may not be possible now.
"Could have done" means that it was once possible to do something, and still may be possible.
I want it more described in professional way, anyone could get???
Well, I am already good with English and most of my vocabulary has been improved by watching english movies and even right now I was thinking to watch greys anatomy in CA to learn about anatomy as well.