看它给你的先行词在从句中做什么成分
如果在从句中做主语或者宾语,那么不用where,why等状语
如果它在从句中做地点状语,那么用where
如果它在从句中做原因状语,那么用why
1、I still remember the school which we visited(及物动词) yesterday
2、I still remember the school where we studied in（不及物动词） many years ago.
第一句中从句缺宾语,用which
第二句中从句缺地点状语,用where