零起点美语-That explains it.

That explains it.

原来如此。
A: Susan, I haven't seen you in the pub for a long time.
B: I have a part-time job now, so I work in the evenings.
A: That explains it.
甲：苏珊，我有好长一段时间没有在酒吧里看到你了。
乙：我目前有份兼职工作，所以都在夜晚上班。
甲：原来如此。