Intro

I had an English teacher who used to tell my class the same joke everyday. He'd say, "knock knock."

And then we'd ask, "who's there?"

"It is I," he always answered in his loud, booming, over-dramatic voice.

Then, when it was our turn to ask, "it is I who?" he always interrupted us with a frustrated, "oh, just another grammar joke."

Anytime anyone else told the joke and answered, "it's me," he would scold the person by saying that there is no me, only "I".  No one ever understood what he was talking about, and sadly he retired my junior year in high school without ever explaining the joke. 

Fast-forward 15 or so years. While reading the chapter in Grammar Snobs about Who vs. Whom, I feel like I finally solved the mystery.  By asking "who is there?", his correct grammatical response was "it is I".  If we asked, "whom is it?" then his correct response would have been, "it's me."  I guess I never knew the rule.  Not sure why he never explained it?  Perhaps he was hoping one of his students would one day figure it out?

"It is I" is a line that me and my friends have repeated for years.  It's become a real inside joke between us.  I actually called a number of them yesterday with my discovery and they all agree that the teacher was trying to get one of his students to explain the rule to him.  Maybe I would have gotten an A?