in which 引导定语从句，放在名词后面修饰该名词作其定语，in which不引导宾语从句，例如：

Few found jobs in which they could make use of their their new skills.

几乎无人找得到能发挥自己新技能的工作（摘自《柯林斯英汉双解大词典》）（本句中，in which引导定语从句，先行词是job，in which指in the job）