关系代词where与from where有何区别
where用作关系副词引导定语从句时，由于它本身在意义上相当于“介词+which”，所以其前通常无需再用介词。如：
This is the hotel where (=in / at which) they were staying. 这就是他们当时住的旅店。
She has a safe in her closet where (=in which) she keeps her jewelry. 她在壁橱内装有一个保险箱存放她的珠宝。
但有时我们也可见到from where的用法，这时因为from是一个比较特殊的介词，因为它有时可以后接介词短语作宾语。如：
Come out from under the table. 从桌子下边出来。
所以，尽管关系副词where在意义上相当于“介词+which”，有时由于语义的需要，也可在where之前使用介词from。如：
We went up to the roof, from where we had a good view of the procession. 我们爬上屋顶，从那儿可以很好地观看游行。