An guy was visiting Oxford University for the first time. He stopped a passing Oxford don and asked, "Excuse me, can you tell me if that's Trinity College I'm looking at?"
The don sneered, "You are probably unaware that you have just ended your sentence with a preposition. You may wish to rephrase your question."
The guy thought for a moment and said,
"Can you tell me if that's Trinity College I'm looking at, YOU JERK!"