关于Which和Where从句区别

题目

关于Which和Where从句区别
lt is a room in which the president works?
lt is a room which the president works in?
it is a room where the president works?
ir is a room where the president works in?
那几句是对的额?

答案

第四个句子.
in【介词】+ which=where
其中的介词,与动词要有联系,就像本句子的work in【在哪里工作】,还可以放在修饰名词的后面.
说白了,就是最后一句中的where 与work in 重复了