b)informal if you say that something is ancient history, you mean that it happened a long time ago and is not important now 很久以前的事,陈年往事〔指很久以前发生、现在已不重要的事〕
It’s all ancient history and I’m not upset anymore.
这都是陈年往事了,我不再生气了。
Examples from the Corpus
ancient history• For one thing, this is not ancient history.• He was so beautiful in those days - listen to me, those days, talking like it was all ancient history.• The world of Lowry's north seems to be ancient history.• Its very imperfection is powerfultestimony of its ancient history, a history of step-by-step change rather than of deliberatedesign.• It has been fashionable in the last twenty years to suggest that there was in ancient history a utopian matriarchy.• Will and I broke up a long time ago - that's ancient history now.• That, too, seemed like ancient history now.• He was very fond of ancient histories, stories and epics of earlier times and heroes.• But my tale of ancient history was less than a generation old.