句子句式剖析问题

Well, there are plenty more where that came from.(专四考试真题选句）

各位老师，我想请教下这句话句式结构怎么样剖析，这里的where引导的从句是修饰哪个的呢? 引导的是什么从句呢，若是定语从句，where=介词+which，难道是came from 介词+which吗？

期待各位老师的回复！

谢谢邀答。这里应该是地址状语从句，修饰前面的句子。比如： He lives where the climate is mild.

Where that came from的意思等于in the place where that came from.