***** NOT A TEACHER *****
Good morning, Moebachelor.
(1) I think it is correct:
Tom: Why didn't you say hello to George yesterday?
You: Well, if I knew him (I do not know him), I would have said hello."
I know VERY little about the conditional. I think (only THINK):
1st = If I HAVE time, I WILL visit you.
2nd = If I HAD time (I do not), I WOULD visit you.
3rd = If I HAD HAD time last week (I did not), I WOULD HAVE VISITED
If I am correct, then your sentence seems to be a combination of
2nd (If I knew) + 3rd (I would have said hello).
I think that grammar books tell us that many times we have to make
combinations in order to express correctly what we mean.
Let's see what others can teach you and me.
Have a nice day!
I think that if George died, and someone asked you why you had not
said hello to George last month, then you could use all 3rd:
If I HAD KNOWN George at that time (I did not), I certainly WOULD HAVE
Student or Learner