in days of old 往日；天荒地老；以前的日子

【例句】
In days of old he was a gallant youth; but those times have long passed away.
以前他是个英俊勇敢的青年，但是，那一段日子毕竟已经过去了。

In days of old, in times of trouble, in flight and exile and wandering, such marriage were often made.
在最古老的年月中，或是在后来战争动乱、放逐流亡的时代里，这样的婚姻都很常见。