I thought there was a difference, in German, between ''this'' and ''that'', so why should I use both here ?
Das can mean this or that in German. I knew a guy whose English wasn't very good and he didn't know the difference.
However, dies (dies nothing, dieser masc., diese fem., dieses pl.) can be used but it's not used as much as das. It's kind of weird. When to use it, you ask?
Well, I don't know for sure. I've heard that it's more of a formal, more powerful this.