英语语法学习：地点状语从句

辨析下列句子是地点状语从句还是定语从句 (1). I live in the room where he used to live. (2). Where there is no rain, farming is difficult or impossible. (3). “Where I live there are plenty of sheep”, said the boy with pride. (4). He has got himself into a dangerous situation where he is likely to lose control over the plane.