Played Civ III a lot - confused trading resources in Civ IV... help

I'm finding it very confusing with the number of items I have left to trade, and it seems like I've traded away my "only copies" of some items.

The AI will pop up with an offer to trade, and I haven't been successfull, as far as I can tell, determining at that point whether I had any extras. Is this information available when they pop up?

When it says Gold(1), that means I only have one right? aghh

No it means the ai wants you to give it 1 gold you proabably have more than 1. Click "care to negotiate" and then "clear table" and you should see that you have two gold resources. I have yet to see the AI offer a trade where I didn't have more than 1 of the resource

You're both right.

If a civ offers to make a trade, it won't ask for something you only have one of yourself.

However, if You have Stone(1) or Silk(1) on your trade list, and you offer it, you are indeed trading away your last Stone or Silk. I'm guessing this is so you can trade for other resources you desperately need (i.e. Stone, Aluminum, Coal, etc)