French language Q&A Forum

I was actually looking for a tutorial here, maybe I'm expecting too much...

I'm confused when to substitute use le, la, or y, my test result says "Have you had your coffee yet?"

So the tutorial is:

"You've already learned that the pronoun y is used to mean there (See Y = There (adverbial pronoun)).

Now here is another usage of y."

This pretty much tells me nothing.

I used "et l'or au milieu du ...." and it was incorrect with the only correct version given being "et le doré au milieu de ..."

Why can't l'or be used here?