古希腊悲剧《俄狄浦斯王》中,有个狮身人面的怪物斯芬克斯,她整天守着一条必经之道让路人猜谜:“什么东西早上是四条腿走路,中午是两条腿走路,傍晚是三条腿走路。”俄狄浦斯回答是人,因为在生命的早晨,人是个小孩,用手脚爬行;生命的中午,人长成壮年,仅双腿便能站立行走;生命的傍晚,人年老体衰,必须借助拐杖。俄狄浦斯答对了,斯芬克斯坠崖而 Ancient Greek tragedy “Oedipus the King,” there is a monster Sphinx Sphinx, she was guarding the passers-by all the way to get rid of riddles: “What is the morning of four legs to walk, noon is Walking on two legs and walking on three legs in the evening. ”Oedipus replied to being human, because in the morning of life, people are children and crawl with their hands and feet; at noon of their life, they grow up and walk with only their legs In the evening of life, when people are old and weak, they must use crutches. Oedipus is right, Sphinx falls off the cliff