定语从句中when可以用哪个介词加which代替

定语从句中when可以换成:in/on/at+which.
具体用哪一个介词,这得根据when所指代的先行词来判断.

如:
The day when I met the famous pop star was the greatest day of my life.
when指代on the day,因此when=on which

Do you still remember the year when we worked together in the company?
when指代in the year,因此when=in which

I'll never forget the moment when I first met Mr Wang.
when指代at the moment,因此when=at which
语关于定语从句关系词where和why、when可以用介词+which代替的用法
when指时间,在定语从句中做时间状语
From the year when he was going to school he began to know what he wanted when he grew up.
本句中when=in which
2.where指地点,在定语从句中做地点状语
This is the house where I lived two years ago.
本句中where=in which
3.why指原因,在定语从句中做原因状语
The reason why he refused the invitation is not clear,
本句中why=for which
when引导定语从句和状语从句的区别
when引导定语从句时，从句一定缺少成分。l will never forget the day when i saw her.
状语从句不缺成分l went to school when
he was sleeping.也就是说在定语从句中，when必须代替主句中得成分，如上句中得the day. 在状语从句中，when只起连词作用，不能取代状语从句中得任何成分。

定语从句中when可以换成:in/on/at+which.
具体用哪一个介词,这得根据when所指代的先行词来判断.

如:
The day when I met the famous pop star was the greatest day of my life.
when指代on the day,因此when=on which

Do you still remember the year when we worked together in the company?
when指代in the year,因此when=in which

I'll never forget the moment when I first met Mr Wang.
when指代at the moment,因此when=at which