Student or Learner
do you know Billgates? or do you know of Billgates?
which one is correct if I'm not friends with him.
I mean, I looked up the word "know" and it says when you say you know somebody, it means you have met him before and talked to him.
however, obviously I've never seen him in person or talked to him.
in this case, should I ask "do you know of him?"
but, casually we ask "hey man, do you know Christina Aguilera?"
if so, what's the difference between "know" and "know of".