若要人不知，除非己莫

Explanation: [Source] Han Mei Sheng, "a letter to admonish the king": "people do not want to hear, Morrow not to words; do not want people to know, Morrow not to." [Explain] To people do not know, unless they do not do it. Means did a bad thing after all to be exposed. [Example] [story] 　　Source: Han Mei Sheng "letter to admonish the king": "people do not want to hear, Morrow not to words; do not want people to know, Morrow not to." 　　Examples: Road is not ~. (Ming Feng Meng, "Awaken the common saying Erlang exploration boots documents")