wherever 和 where 杂用

wherever did you get hold of that idea?
其实正确的来说就是
你怎么会有这种想法?很多时候用在反问句得形式中.也许根据书本上的语法来讲是讲不太通,但是在美国这种说法很常见.可是说成How on earth did you come up with this kind of an idea or How can you come with such an idea like this?!
可以用where来代替,但是语气就变了,变成是期待一个回答的问句.而不是不期待答案的反问句.