which和in which 的不同

in which意思是在哪里！与where意思相同which指哪一个！

并非如此解释,有时在定语从句中which 前出现的介词必须和后面的动词结合一起看待.
《例》the farmer uses wood to build a house (in which) to store grain.
有些动词后面习惯上配置了介词形成一个短语来更完整的表达意思,像这句中的 store 是储存、储藏的意思,store in ... 存放在...里.当这样的短语在从句中出现用以补充说明主句时,会把介词放在连词 which 之前,也属于一种倒装语法.
the farmer store (something) in a house.
the farmer built a house in which to store (something).
不止是最常见的 in, 其他介词如 at, on, by, with ... 都会出现,下面例句还有 under 的呢：
he has lost the key to the drawer__the papers are kept. a.where b on which c uner which d which 为什么选c,介词加关系代词而不是选d关系代词呢?
道理和第一个例子一样.
A)He keeps the papers under the drawer.
and => B) he has lost the key to the drawer
A+B) He has lost the key to the drawer (under which) the papers are kept.
希望能对你的理解有所帮助.