关系副词 when / where / why
先行词是时间、地点、原因时，用关系副词引导定语从句。
the day when … / the place where … / the reason why …
要点
- when 的先行词是时间，where 的先行词是地点，why 的先行词是 reason。
- 关系副词在从句里作状语，所以从句成分要完整。
- 判断用关系代词还是关系副词，看从句缺主语/宾语，还是只缺状语。
- where 还能接在抽象地点名词后面：point、case、situation。
- when 与 where 常能整个省掉：the day (when) we met ／ the place (where) he lives —— 省下来从句仍然通顺；这与"作宾语的关系代词可省"是两条不同的省略。
- reason 后面那句若缺宾语，就不能用 why：The reason that / which he gave for being late was not true.（gave 要有东西）；He was late, and the reason why he was late is clear.（从句不缺成分）才轮到 why。
- when 也能挂在逗号后面做非限制性补充：He graduated in 1998, when he was twenty. —— 逗号那一头管着"不许用 that"，但不禁关系副词。
例句
I still remember the day when we first met.
我还记得我们初次见面的那一天。
This is the school where I studied ten years ago.
这是我十年前读书的学校。
That is the reason why he was late.
那就是他迟到的原因。
We have reached a point where we must make a choice.
我们已经到了必须做出选择的地步。
Do you remember the evening when we danced?
你还记得我们一起跳舞的那个晚上吗？
The reason that he gave for being late was not true.
他为迟到说的理由不成立。
易错提示
- 从句成分完整就用关系副词，缺主语或宾语就用关系代词。
- why 只接 reason，别用在别的先行词后面。
- where 后面那一串必须自己站得住：This is the school where I studied.（study 不带宾语也行）对比 This is the school which / that I visited.（visit 要有宾语）—— 从句要不要东西，决定用副词还是代词。
- 把从句单独抄出来看一眼它完不完整，是这一条唯一可靠的判法：补得回一个状语就用 when / where / why，补不回主语或宾语就用 that / which / who。