Kathy and Polly were friends but they liked playing tricks
on each other.
  One day Kathy met Polly in the street. She said, “Hi, Polly.
It’s good to see you.”
  “How can you see me when I’m not here?” Polly asked.
  “What do you mean, you’re not here?” Kathy asked. “Of
course you’re here.”
  “No, I’m not,” Polly said, “and I’ll bet you ten dollars that I

can prove I’m not here.”
  “All right,” said Kathy. “Ten dollars. Now prove you’re not
here.”
  “Easy,” Polly said. “Am I in Hong Kong?”
  “No,” said Kathy.
  “Am I in Paris?”
  “No,” said Kathy.
  “If I’m not in Hong Kong and I’m not in Paris,” Polly said,
“then I must be somewhere else. Right?”
  “Right,” said Kathy. “You must be somewhere else.”
  “Exactly,” said Polly. “And if I’m somewhere else I can’t be
here, can I? Ten dollars, please.”
  “That’s very clever, Polly,” Kathy said, “but I can’t give you
ten dollars.”
  “Why not?” asked Polly. “We had a bet.”
  “Certainly we had a bet,” Kathy laughed, “but how can I
give you ten dollars if you’re not here?”

                不在这里
  凯西和波莉是好朋友，但是她们喜欢开玩笑。
  一天凯西在街上遇见了波莉。她说：“嗨，波莉。很高兴见到你。”
  波莉问：“我不在这里，你怎么看见我的啊？”
  凯西问：“你的意思是你不在这里？但是你不就在这里吗？”
  “不，我不在这里，”波莉说，“我跟你打赌，赌10美元，我可以证明
我不在这里。”
  “好吧，”凯西说，“10美元。现在你就证明你不在这里吧。”
  “很简单。”波莉说，“我在香港吗？”
  “不在。”凯西说。
  “那我在巴黎吗？”
  “不在。”凯西说。
  “如果我不在香港也不在巴黎，”波莉说，“那么我一定在其他地方
了，对吧？”
  “对呀！”凯西说，“你一定在其他地方。”
  “太对了！”波莉说，“如果我在其他地方，那么现在我就不在这里，
我说的对吧？10美元，拿来吧！”
  “太聪明了，波莉。”凯西说，“但是我不能给你10美元。”
  “为什么不给？”波莉说，“我们已经打赌了啊。”
  “当然啦，”凯西大笑说，“既然你不在这里，我怎么给你钱呀？”