old acquaintance
... [old system; old rules] 旧制度;旧例 [old acquaintance] 旧友;旧知;故旧;旧交 [former appearance] 旧时的样子 ...
former friend
... 尽人皆知 a household name 旧知 former friend; old acquaintance 理性知识 rational knowledge ...
Old know
浅谈化学课的导入艺术 --中国期刊网 关键词】导入;旧知;魔术;谜语;悬念 [gap=408]Key words】Ducting;Old know;Magic;Riddle;Hang to read
旧知