it's my life

A teacher was quizzing her students. "Johnny, who signed the Declaration of Independence?" He was older than some of the others. He said, "Damned if I know."
She was a little put out by his swearing, so she told him to go home and to bring his father with him when he came back.
Next day, the father came with his son, sat in the back of the room to observe, as the teacher requested. She started back in on her quiz and finally got back to the boy. "Now, Johnny, I'll ask you again. Who signed the Declaration of Independence?"
"Well, hell, teacher," Johnny said, "I told you I didn't know."
The father jumped up in the back, pointed a stern finger at his son, and said, "Johnny, if you signed that thing, you damn well better own up to it!"