To make a point, let me repeat a known fact about the German tennis player Steffi Graf, and when Graf was in the final rounds of major tournaments, her father was known to bet against her.

• 也容我在此重复一个故事：网球女将格拉夫的父亲就是以"赌"来买"保险的，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，认为赌女儿输球，女儿就会赢球。