题目内容：

Once a man got on a bus for New York. He hid in toilet, because he did not want to pay. But a passenger saw her. She tapped the person in front of her on the shoulder and say, "There's a bum(流浪汉) in the toilet. Tell the bus driver." The message was past from person to person. But anywhere along the way, it changed. The bus driver was told that there was a bomb in the toilet. He immediate stopped the bus and telephoned the police. When the police came in, they told the passengers to get off the bus or stay far away. Then they closed the highway. This soon caused a 15-miles-long traffic jam. Under the help of a dog, the police searched for two hours. Of course they found no bomb!