where引导的定语从句 This is the village that/which he lived in when he was young.. This is the village in which he lived when he was young. 在上句中，in which代表in the village表 示的是He lived （他居住）的地点（小村 庄），所以in which合在一起在从句中充当 He lived的地点状语，这时in which可以用 where替换 This is the village where he lived when he was young.
所以，当先行词是表示地点的名词，在从句 中充当地点状语，表示从句的动作所发生的 地点时，可以由关系副词where来引导，这时 where=介词+which
如：Here is a big desk where there are lots of books. =Here is a big desk in which there are lots of books. =Here is a big desk that/which there are lots of books on.
Do you remember the hotel where we stayed last week? =Do you remember the hotel in which we stayed last week? =Do you remember the hotel that/which we stayed in last week?
所以在判断是否用where时一定要注意在关系词 前或动词后是否有介词，只有前后都没有介词时， 才能用where.
再看下面句子的区别： This is the building where my sister works . This is the building that/which was built last year. 在1.句中，这个building（大楼）是my sister(我姐姐) 的工作（works）地点,在 从句中充当的是地点状语，所以用where. 而在2.句中，这个building（大楼）是在 去年被建成的，在从句中充当的是主语， 必须用that/which.
再看下面两个句子： 1.I miss the school where I studied for three years. 2.I miss the school that/which we visited last week. 在1.句中，这个school（学校）是I我 studied（学习）的地点，在从句中充 当的是地点，所以用where. 在2.句中，这个school（学校）是we （我们） visited（参观）的对象，在从 句中充当的宾语，必须用that/which.
所以在判断是否用where时，一定要注意 以下情况: 1.当关系词所代表的先行词在从句中充当 主语或宾语时，用which/that. 2.当定语从句中的谓语动词是visit时，用 which/that. 3.当关系词前有介词时，用which., 当从 句中谓语动词后有介词时，用which/that. 4.只有当关系词所代表的先行词在从句中 充当地点状语，又没有介词时，才能用 where.
1.He doesn’t like the house where he has lived for ten years. 2.This is the room where we stayed just now. 3.Tom wants to see the factory where he worked when he was young. 4.We like the farm where there are many horses and sheep. 5.This is a beautiful park where many children have fun.