用铜做镜子,可以整理好一个人的穿戴;用历史作为镜子,可以知道历史上的兴盛衰亡;用别人作自己的镜子,可以知道自己每一天的得失。Take copper as a mirror, I can tidy up my clothes; take people as a mirror, I will know what I do is right or not; take history as a mirror, I will know how the things rise and fall