After fumbling about for a few moments, he opens the door to find an old man, who greets him with a big smile and says:

“May I come in? I worked in this very room thirty years ago when I was a professor at this college.”

“Sure!” replied the professor. “Be my guest!”

The old man examined the room, fondly remembering everything.

He said, “The same old room, the same old wooden table, the ventilator and the same old window that opens to the garden. And the same old desk.”

When examining it, he noticed there was a young girl hiding under the desk.

The younger professor got alarmed and said,

“Don’t mistake me.  She’s my daughter.  She dropped her earring and is searching for it…”

The old man grinned and said, “… And the same old story.”