定语从句（一）｜定语从句①：高考必考的 5 个关系代词 + 只用 that 的 5 种情况
高中英语语法精讲 · 第 13 期
导语
先看学生作业里的一句高频错句：
❌ The man who I spoke to him is my English teacher.
看着挺完整，其实从句里的 him 是多余的——关系代词 who 已经代替 him 作了介词 to 的宾语，再写 him 就"撞车"了。定语从句年年考、年年错，错就错在这种"想给从句补全"的冲动上。今天先把关系代词一次讲清。
一、先建立地图：5 个关系代词
定语从句就是"跟在名词后面、给这个名词补充说明"的从句。被修饰的名词叫先行词，从句开头的连接词叫关系代词——它有双重身份：既连接从句，又在从句里充当主语或宾语。
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选词只需三步：
第一步：找先行词（人 or 物？）→ 第二步：看从句缺什么成分 → 第三步：缺主语或宾语，就在 that / which / who 里选。
记住：关系代词作从句成分后，从句里不能再出现重复的代词或名词——这是导语那句话错的根源。
二、10 个高频易错点
1. 三步法走一遍：先"缺什么"，再"选哪个"
以"这就是我昨天买的那本书"为例：
先行词 the book（物）； 从句缺宾语（I bought ______）； 选 that / which（作宾语还可省略）。
✅ This is the book (that/which) I bought yesterday.（这就是我昨天买的那本书。）
判断从句缺不缺成分，是定语从句第一基本功——语法填空里先填出引导词，再检查成分，两边互相印证。
2. 只用 that 的 5 种情况（高考必背）
以下情况关系代词只用 that，不能用 which：
口诀：不定、序数、最高级，only、very、人和物，五个场合用 that。
3. who 还是 whom？一句话分清
从句缺主语 → who：The man who helped me is a doctor.（帮我的那个人是位医生。） 从句缺宾语 → whom（正式）：The student whom the teacher praised is my deskmate.（被老师表扬的那个学生是我同桌。） 口语中作宾语常用 who 代替 whom，但介词之后只能用 whom：
✅ This is the friend with whom I traveled to Xi'an.（这是和我一起去西安旅行的朋友。） ❌ This is the friend with who I traveled to Xi'an.
4. whose 不只指人，指物也可以
a writer whose works are widely read（一位作品被广泛阅读的作家） the house whose windows face south（窗户朝南的那座房子）= the house the windows of which face south
记法：whose = 先行词的"的"，在从句里作定语，后面必须紧跟名词。指物时可用 "of which" 替换。
5. 作宾语可省略，作主语不能省
宾语可省：The novel (that/which) I borrowed is due tomorrow.（我借的那本小说明天到期。） 主语不可省：Anyone who wants to join the club should sign up today.（想加入社团的人今天要报名。）
陷阱：省略只发生在"关系代词紧跟动词作宾语"时。若前面有介词，不但不能省，还不能用 that：
✅ the village in which I grew up（我长大的那个村庄） ❌ the village in that I grew up
6. 从句谓语的单复数，看先行词，不看关系词
Those who have finished the test may leave.（做完试卷的人可以离开。）→ those 是复数 He is one of the students who have passed the exam.（他是通过考试的学生之一。）→ 先行词是 the students He is the only one of the students who has passed the exam.（他是学生中唯一通过考试的。）→ 先行词是 the only one
口诀：one of + 复数，看复数；the (only) one of + 复数，看单数。
7. 从句里不许"多此一举"
定语从句最大的改错考点就是导语那类句子——关系代词已经作了成分，从句里不能再放一个代词：
❌ The house which we live in it is very old. ✅ The house which/that we live in is very old.（我们住的那座房子很旧。） ❌ The teacher who I talked to him is patient. ✅ The teacher who I talked to is patient.（我和他谈过的那位老师很有耐心。）
短文改错里一旦看到"定语从句 + 多余代词"，直接删。
8. that 不能引导非限制性定语从句
逗号隔开、只作补充说明的从句叫非限制性定语从句（下期详解），它只能用 which / who，不能用 that：
❌ My father, that is a doctor, works in a hospital. ✅ My father, who is a doctor, works in a hospital.（我父亲是位医生，在医院工作。） ✅ The Great Wall, which attracts millions of visitors every year, is in China.（长城每年吸引数百万游客，它在中国。）
9. the way 作先行词：三种写法都对
先行词是 the way（方式）时，从句可用 that / in which 引导，也可以什么都不用：
I don't like the way (that / in which) he talks to his mother.（我不喜欢他跟他妈妈说话的方式。）
三选一都可以，唯独不能选 which。语法填空给 which 当选项时，直接排除。
10. what 不是关系代词——语法填空头号陷阱
what 只能引导名词性从句（第 11 期讲过），不能引导定语从句。语法填空里先行词前面摆着，却给了 you 一个 what，必是干扰项：
❌ The book what I bought is interesting. ✅ The book that/which I bought is interesting.（我买的那本书很有趣。） 对比：What I bought yesterday is a novel.（我昨天买的是一本小说。）→ 此句无先行词，才是 what 的地盘。
记法：有先行词用 that/which，没先行词才轮到 what。
三、高考风格演练（4 题）
1. Everything ______ can be done has been done to save the injured boy. A. which B. that C. what D. who
答案：B 解析：先行词 Everything 是不定代词，关系代词只用 that；从句缺主语，不可省略。what 不能引导定语从句。
2. This is the most interesting story ______ I have ever heard from my grandmother. A. which B. that C. it D. what
答案：B 解析：先行词被最高级 the most interesting 修饰，只用 that。"I have ever heard" 缺宾语，that 也可省，但选项中没有省略项。
3. He is the only one of the students who ______ chosen to take part in the English speech contest. A. have been B. has been C. have D. is being
答案：B 解析：先行词是 the only one（唯一那个人），谓语用单数；"被选中"用被动 has been chosen。去掉 only，先行词变为 the students，才选 A。
4. 短文改错：The teacher who we visited him last year is now working in Beijing.
答案：删去 him 解析：who 已作 visited 的宾语，从句中再保留 him 属于成分重复，删去即可。
四、随堂练习（5 题）
1. Do you still remember the days ______ we spent together in the countryside? A. when B. which C. what D. in which
2. The girl ______ mother is a nurse studies hardest in our class. A. who B. whom C. whose D. that
3. Is this the museum ______ you visited last summer? A. where B. in which C. the one D. that
4. Those who ______ against the plan, please raise your hands. A. is B. are C. was D. has been
5. 短文改错：The novel which I borrowed it from the library is worth reading twice.
参考答案
- B
。先行词 the days 在从句中作 spent 的宾语（spend the days），用 which/that（可省）。若从句不缺宾语（如 we stayed together），才用 when。 - C
。mother 前需要定语"她的"，用 whose。 - D
。visited 缺宾语，先行词 the museum 指物，用 that。A/B 意为"在博物馆里"，但从句不缺地点状语。 - B
。先行词 Those（那些人）是复数，谓语用 are。 删去 it。which 已作 borrowed 的宾语，it 重复。
五、一句话总结
定语从句第一课，三句话带走：
- 选词三步走：找先行词 → 看从句缺什么 → 缺主语宾语才选 that/which/who。
- 不定代词、序数词、最高级、only/very、人和物——五种场合只用 that。
- 关系词已在从句里当了差，从句里就不能再有代词多此一举。
下期预告： 定语从句（二）——when / where / why 到底怎么选？"介词 + which" 的介词从哪来？非限制性定语从句里 that 为什么不能用？收尾定语从句专题。
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