出处：按学科分类—语言、文字 中国对外翻译出版公司《汉英成语词典》第254页（264字）
遭受创伤之后，回想所受痛苦，有警惕未来之意，例今天我们应该痛定思痛，深刻领会过去的内忧外患是怎样造成的。
To draw a lesson from the bitter past，we should look back and figure out the reasons why our country was inflicted with turmoil within and agression from abroad．