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."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.""Easy,"Polly said."Am I in Hong Kong?""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,"side 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.""Certainiy we had a bet,"Kathy said,"but how can I give you ten dollars if you're here?"And with a laugh she walked away.