Queen Elizabeth and the Queen Mother

Who is Queen Elizabeth? I am an American, I am not familiar with the idea of a monarch or a royal family, but I found myself wanting to understand England's Royal Family tree.
So let me break it down:

Standard or Metirc

So I was out for coffee with a friend and we were discussing doing work overseas.
I said I couldn't work  overseas because I think it would be hard to convert everything to the metric system. I am so used to working in ______ system. I drew a complete blank. What the hell is the system we use here in the United States.

I figured it out... its the standard system.

I guess I learned something.