基本定语从句（who、which、that）

定语从句是一个用来进一步说明名词的从句——可以说明某人是谁，或某物是什么。两个短句可以合并成一个自然流畅的句子：

The woman lives next door. She teaches music. → The woman who lives next door teaches music.

掌握这一结构后，你就能用一个流畅的句子描述人物、地点和事物，而不必拆成几个简短的句子。

简要规则： 指人用 who，指物用 which，两者皆可用 that。定语从句紧跟在它所修饰的名词之后。

Who、which 还是 that？

选择哪个关系代词，取决于你所描述的对象：

在限制性定语从句（不带逗号、用于明确所指人或物的从句）中，that 通常可以替换 who 或 which：the woman that called、the book that I bought。在这个阶段，用 that 通常比较稳妥。但在介词之后要避免使用 that（the house in which I grew up，而非 ❌ the house in that I grew up），在用逗号隔开的非限制性定语从句中通常也不用 that——这些内容留到后面再学。

汉语的修饰成分放在名词前面，用"的"连接：住在隔壁的女人（the woman who lives next door）。英语则相反，定语从句放在名词后面，并以 who／which／that 引导。这种语序的转换是英语定语从句最需要适应的地方。

句子结构：名词＋关系代词＋从句

定语从句紧跟在它所修饰的名词之后：

【名词短语】＋ who / which / that ＋【从句其余部分】

• That's the teacher who taught me French.
• Is this the bus that goes to the airport?
• I love the jacket which you were wearing yesterday.
• The café that we went to last week is closed now.

定语从句必须紧靠所修饰的名词。如果有关系代词，它位于从句开头。将从句移到句子末尾会破坏句意的连贯：❌ The teacher taught me French who was very strict. → ✅ The teacher who taught me French was very strict.

关系代词作主语

当 who／which／that 是定语从句的主语（由它来执行动作）时，关系代词不可省略：

• the film that won the award —— that 获奖了（主语）
• the colleague who helped me —— who 帮助了我（主语）
• a dog that barks all night —— that 叫了一晚上（主语）

关系代词作宾语——以及省略关系代词

当 who／which／that 是定语从句的宾语——无论是动词宾语还是介词宾语——从句中已有独立的主语（I、we、she 等）：

• the film that I recommended —— I 推荐了它；that 是宾语
• the colleague who I called —— I 打电话给那位同事；who 是宾语
• the bag which she bought —— she 买了它；which 是宾语
• the keys that you were looking for —— you 在找；that 是 for 的宾语
• the café that we went to —— we 去了；that 是 to 的宾语

在这些情况下，可以完全省略关系代词——这在日常英语中非常自然：

实用判断方法：在简单句中，如果关系代词后面已经有 I、you、we 或名词短语作主语，说明它很可能是宾语——通常可以省略。如果关系代词本身执行动作、后面没有其他主语，则必须保留。

关于地点的说明

表示地点时，英语常用 where 表示"在其中／在那里"：the café where we met、the city where I grew up。使用 that 或 which 时需保留介词：the café that we met in / the café we met in。在这个阶段，where 是最简单的选择。

常见错误

• ❌ She is the doctor which treated me. → ✅ She is the doctor who treated me.（指人用 who，不用 which）
• ❌ That's the book who I told you about. → ✅ That's the book that I told you about.（指物用 which 或 that）
• ❌ The man who he lives next door is a chef. → ✅ The man who lives next door is a chef.（who 已充当主语，he 多余）
• ❌ Is this the restaurant that it was on TV? → ✅ Is this the restaurant that was on TV?（that 已是主语，多余的 it 不需要）
• ❌ I found the book that I bought it. → ✅ I found the book that I bought / the book I bought.（关系代词已代表 it，不必再重复）

快速练习

用 who、which 或 that 填空。如果关系代词可以省略，请加括号。

1. That's the woman ____ works with my sister.
2. The laptop ____ I bought last year has stopped working.
3. Is that the film ____ won five Oscars?
4. I found the keys ____ you were looking for.

要点总结

• 定语从句对名词起补充说明作用，紧跟在名词之后。
• Who 指人，which 指物，that 指人或物（安全的默认选择）。
• 句子结构：名词 ＋ who／which／that ＋ 从句。
• 如果关系代词是从句的主语（没有其他成分能执行该动作），则必须保留。
• 如果关系代词是宾语（后面已有主语），则可以省略：the film I recommended ＝ the film that I recommended。
• 不要用多余的代词重复名词：❌ the man who he lives next door → ✅ the man who lives next door；❌ the book that I bought it → ✅ the book that I bought / the book I bought。