I studied at this place where I spent three years.
定语从句没错了.place先行词,where引导定语从句修饰place.
你们老师是要你们分定语从句和状语从句吧?
She found her wallet where she lost it.地点状语从句
Now he works in the factory where he father used to work.where引导定语从句,表示地点.先行词the factory.
状语从句没有先行词的,定语从句一定要有先行词.这个用来划分定从和状从最好用了.
修改前的答案很有问题,是我没仔细分析.现在的才是对的,抱歉了.