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252页（200字）
指现在是对的，过去错了，含有悔悟之意，例经过一番教诲，他终于了悟今是昨非，决心痛改前非。
After a period of discussion，he finally realized his past misdoings and was determined to turn a new leaf