I've got this problem:
I know I can say that something is "on the left" or "to the left". But is it true that when you add "of" you can no longer say "on" but you need "to"? In practice:
The pencil is on/to the left. <--- both ok
The pencil is on/to the left of the book. <--- only "to" is ok

Anyway I know I can say "on the left of the screen" if I'm talking about something that is on the screen. But if it is not on the screen, I have to say "to the left of the screen".

Is that true or did I dream of it some night? Thanks Emotion: smile

My HO is this:
"On the left of smth" means the object is on something, on the left side of it. — "On the left of the shelf".

EDIT: Seems I am not right.
Well, yeah... maybe. But.. I still don't know. Emotion: smile
Students: We have free audio pronunciation exercises.
Intelligence reports:
There have not been found much difference, so they're both correct and mean the same.