定语从句为什么用which 不用when

Question

定语从句为什么用which 不用whenI will never forget the days which we spent together in the country
Do you still remember those days which we spent in London very happily?
为什么这两句话中引导词不填when ，从句中不是缺少时间状语吗？

Answer 1

这个问题是这样的。
用when，where还是which与先行词的含义是时间、地点无关系。
只和从句缺什么成分有关。Do you still remember those days which we spent in London very happily?这句话，是spend sth. in London，因此该句缺宾语，填which。
另一个例子，Do you still remember those days when we traveling in London very happily?这句话就不缺成分，就该用when了，你明白了吗？追问

Do you still remember those days when we traveling in London very happily?这句话we 和traveling中间是否缺少be动词？

Answer 2

当先行词是scene ,stage .case .point occasion …之类在句中做状语用where when 多数引导时间状语从句 which 在句子中指物时，或引导非限性定语从句，一般，where 可用prep+which 代替。