前事不忘，后事之师

Explanation: Teacher: reference. Do not forget the lessons of the past can serve as a reference for future work. 　　Usage: The main predicate; as the predicate attribute; for human 　　Source: Han Liu Xiang "Warring Zhao policy a": "s not forget the former things, guide for the future." 　　Examples: Southern Song Fan Ye "Han Zhang Heng Chuan": "Luxury, Indulgence flatter slower, not barbarians fresh kill, ~ also." Thesaurus:  Limber The cover, Carriage(s) occupied by one's entourage Zhijian