This is the school in which I studied. 等同于 This is the school where I studied.定于从句不一定是用which、that引导的，因为它们引导的一般都是指物体的宾语。还有定语从句是用who或者where引导的，who一般指人：He is a great man who broke the world record.where指地点，这个就是你举得例子了。而修饰地点的定语从句，有两种方式：1直接用where；2用介词+which的形式。一般很少有用where引导的状语从句。第二个句子，原来的意思可以表达为：I am not young. You agree...
