that's another story 题外话、那是另外一码事了、那就另当别论了、这个故事改天再说。

【例句】
I'd met him at a dance I'd gone to on my own. But that's another story.
我有一次独自去参加舞会时遇上了他。但那是题外话了。

A little lance adjustment, but that's another story.
一些兰斯的调整，不过那是另外一码事了。