定语从句——关系词的选择
一、定语从句回顾
定语从句在句中作定语，修饰一个名词或代词。被修饰的词叫先行词。
结构： 先行词 + 关系词 + 从句
二、关系代词的选择
| 关系词 | 指代 | 充当成分 | 例句 |
|---|---|---|---|
| who | 人 | 主语、宾语 | The boy who is singing is my brother. |
| whom | 人 | 宾语 | The man whom you met is a teacher. |
| which | 物 | 主语、宾语 | The book which I bought is interesting. |
| that | 人/物 | 主语、宾语 | The movie that we saw was great. |
| whose | 人/物 | 定语（所属关系） | The girl whose mother is a doctor is my friend. |
三、只能用that的情况
必须用that，不能用which： 1. 先行词是 all, little, few, much, everything, nothing, something, anything 2. 先行词被 序数词 修饰（the first, the second...） 3. 先行词被 最高级 修饰（the best, the most...） 4. 先行词被 the very, the only, the same 修饰 5. 先行词既有人又有物
例句：This is the best film that I have ever seen. 例句：I know the only person that can help us.
四、只能用which的情况
- 非限制性定语从句（有逗号隔开）
- 关系词前有介词
例句：The house, which I bought last year, is very old.（非限制性） 例句：The tool with which he fixed the car is mine.（介词+which）
五、关系副词
| 关系副词 | 指代 | 充当成分 | 相当于 |
|---|---|---|---|
| when | 时间 | 时间状语 | in/at which |
| where | 地点 | 地点状语 | in/at which |
| why | 原因 | 原因状语 | for which |
六、实战练习
填入合适的关系词： 1. The woman _ lives next door is a doctor. 2. This is the school I studied. 3. I'll never forget the day __ I met him. 4. The reason _ he was late is that he got up late. 5. The house ___ windows face south is my home.
答案：1. who/that 2. where 3. when 4. why 5. whose