Wang Bin is a football fan. There is a football match between Chinese team and American team. He wants to watch it. He comes to the box office（ 售 票 处 ） and gives the clerk 10 yuan. The clerk says, "Please give me another 10 yuan. The price of a ticket is 20 yuan. " "Why?" says Wang Bin, " I just watch Chinese team. I don't want to watch the other team at all. Do you want me to buy a ticket for them? No, no, no…"