Let me repeat a story of the German tennis player Steffi Graf. When Graf was in the major tournaments,her father was known to bet against her. Some sports journalists with no knowledge of futures speculated that the senior Graf was superstitious.

• 容我在此重复一个关于德国网球运动员格拉夫故事：格拉夫的父亲在女儿参加重大比赛时，总是下注赌女儿会输，不懂期货原理的体育记者们都以为他迷信。