智者千慮,必有一失 [ㄓˋ ㄓㄜˇ ㄑㄧㄢ ㄌㄩˋ , ㄅㄧˋ ㄧㄡˇ ㄧ ㄕ; zhi4 zhe3 qian1 lu:4 , bi4 you3 yi1 shi1] lit. a wise person reflecting a thousand times can still make a mistake (idiom); fig. nobody is infallible ◄ ►