Again, I'm keeping this in the same thread because I don't want y'all to get upset...
A friend teaches me a lot of stuff on business. And I say to her:
Wow! I can/could learn a lot from you.
What's the difference here? I sense a subtle difference in even the most minute nuance. No?
I like to look at the practical side of things. If it is a friend who you have, in fact, learned a lot from, you could say:
I have learned a lot from you.
If, on the other hand, you are talking to someone who you would like to be your mentor it makes more sense to say:
I could learn a lot from you.
(I realize I haven't talked about the difference between
can and
could, but while that might be relevant in a different context, it is not, I think, relevant in this context.)