你说的情况在定语从句中常出现.situation ,case ,point作先行词时,关系词一般情况下用where.如：I have reached a point in my life_where_I am supposed to make decisions of my own.It's helpful to put children...at which=where?where=介词+which；其中介词可根据句意表达和搭配，用合适的介词。如：Thisisthe point【某地方；地点】_at_which=where_the river divides。This is the farm _on which_they usuallywork.