交浅而言深者,愚也;在贱而望贵者,惑也;未信而纳忠者,谤也。  
释义:跟交情浅的朋友说过深的话题,是愚蠢的;生活贫困的人总是希望得到富贵者的施舍,是糊涂的;没有取得他人的信任就进献忠言,会被误解为批评。  
Education is the foundation of sustainable forestry—people protect what they understand.