Question

in which=where，那什么which等于when？还有什么of which=什么？

Answer 1

on which / at which / by which 都可能= when
ofwhich=whose

Answer 2

ofwhich=whose

Answer 3

定语从句中，有时where、when等可以与介词+which结构相互替换：
介词的使用是根据先行词而言的。
例如：I'll go to the park where I can fly a kite.我将去公园，在那里我可以放风筝。此处where=in which，因为in the park。
I‘ll go to the station where I'll pick up my brother. 我将去车站，在那里我将接我的弟弟。此处where=at which，因为at the station.
至于when的情况，也是看先行词：
例句：It was five o’clock at which I was doing my work. 那时候是五点，我正在工作。
It was Sunday on which I had a picnic. 那是一个周日，我们去野餐了。
of which是指与先行词是从属关系。
例句：I have some friends ，of which Tom is the best one.
并不是所以情况下都可以和介词+which结构相替换，得看where，when等疑问词是否能在不引起歧义的情况下表达出相应的含义。

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