CLASE DE INGLÉS 463 Telling stories with "when" and "while" part 1

Complete the anecdote.
Years ago, ______ my friend and I were in middle school decided to write our names on a one-dollar bill for fun. We spent the money and forgot about it. Then, one night about 20 years later _________ I was waiting for a bus. I saw a dollar bill on the street. I picked it up and my name was on it! It was the same bill we wrote on! ________ I think of it now, I'm amazed!