2027届高考英语一轮复习定语从句知识点整理讲义

重点口诀  主句完整，先找先行词；从句缺主语/宾语/表语，用关系代词；从句主干完整但缺时间/地点/原因状语，用 when/where/why；whose 是“名词前缺定语”，要单独记。

判断顺序

直接选什么

关键判法（先划从句，再选词）

第一步：主句完整

定语从句 = 修饰语

关键：定语从句不补主句成分，删去定语从句后，主句仍成立。

例：The book that I bought is useful. → 主句：The book is useful.

从句缺主语/宾语/表语

that / which / who / whom / as

关键：关系词要进入从句作主干成分。

例：The man who spoke first is my teacher. who 作主语。

例：The book that I bought is useful. that 作宾语。

从句主干完整，缺时间状语

when

关键：从句有主语和谓语，不缺主干成分，只缺“在那个时候”。

例：I remember the day when we first met. = on which we first met.

从句主干完整，缺地点/语境状语

where

关键：从句不缺主语或宾语，只缺“在那里/在这种情况下”。

例：This is the school where I studied. / We reached a point where we had to decide.

从句主干完整，缺原因状语

why

关键：先行词通常是 reason，只缺“因为这个原因”。

例：I do not know the reason why he left. = for which he left.

特殊：名词前缺定语

whose

关键：whose + 名词，表示“谁的/其”；它作定语，不归入缺主语/宾语。

例：The girl whose mother is a doctor studies hard.

总原则  从句通常从引导词开始，但不一定都到句末。正确做法是：先找到引导词，再找到这个从句自己的谓语结构；一旦从句结构完整，后面若出现主句谓语、逗号/句号，或新的引导词，就要判断从句边界。

主句

引导词

外层从句

内层从句

边界规则

彩色划分例句

课堂判断方法

规则1：句末型

从引导词开始，到句子结束

例1：I still remember the day when we first met.

划分：从句：when we first met；修饰 day。

例2：This is the school where I studied.

划分：从句：where I studied；修饰 school。

例3：Please tell me the reason why you were absent.

划分：从句：why you were absent；修饰 reason。

例4：I like the book that you recommended.

划分：从句：that you recommended；修饰 book。

例5：She lives in a house whose windows face the sea.

划分：从句：whose windows face the sea；修饰 house。

1. 从句放在句末，后面没有主句成分。

核心：从关系词开始，后面一直是修饰先行词的内容，直到句号结束。

常见：when/where/why 句末定从，或 that/which/who/whose 句末定从。

规则2：插入型

从引导词开始，数够从句谓语；遇到主句谓语就停

例1：The book that I bought yesterday is useful.

划分：从句：that I bought yesterday；主句：The book is useful. bought 是从句谓语，is 是主句谓语。

例2：The girl whose mother is a doctor studies hard.

划分：从句：whose mother is a doctor；主句：The girl studies hard. is 是从句谓语，studies 是主句谓语。

例3：The man who spoke at the meeting is my uncle.

划分：从句：who spoke at the meeting；主句：The man is my uncle。

例4：The city where I was born has

2. 从句夹在主句中间，不能一直划到句末。

核心：先划出从句自己的谓语；从句结构完整后，后面的谓语常常是主句谓语。

提醒：判断“第二个动词”时，只看有限谓语，不把 to do、doing、done 当主句谓语。

changed greatly.

划分：从句：where I was born；主句：The city has changed greatly。

例5：The reason why he refused the offer remains unclear.

划分：从句：why he refused the offer；主句：The reason remains unclear。

规则3：嵌套型

从引导词开始，遇到下一个引导词，先划内层从句

例1：The book that I bought when I was in Beijing is useful.

划分：外层从句：that I bought when I was in Beijing；内层从句：when I was in Beijing。

例2：The village where we stayed when the storm came has become famous.

划分：外层从句：where we stayed when the storm came；内层从句：when the storm came。

例3：The reason why he left before the meeting ended was never explained.

划分：外层从句：why he left before the meeting ended；内层从句：before the meeting ended。

例4：The girl whose mother works in the hospital where my aunt is treated is kind.

划分：外层从句：whose mother works in the hospital where my aunt is treated；内层从句：where my aunt is treated。

例5：I visited the museum which my teacher recommended when we studied history.

划分：外层从句：which my teacher recommended when we studied history；内层从句：when we studied history。

3. 定语从句里面还可以套别的从句。

核心：遇到下一个引导词时，先把内层从句划完，再回头判断外层定语从句是否结束。

提醒：内层从句不一定也是定语从句，也可能是时间、地点等状语从句。

规则4：标点型

从引导词开始，看逗号或句号收束

例1：My father, who is a doctor, works in this hospital.

划分：从句：who is a doctor；两个逗号之间是非限制性定语从句。

例2：He passed the exam, which made his parents proud.

划分：从句：which made his parents proud；which 指前面整句。

例3：As is known to all, practice makes perfect.

划分：从句：As is known to all；逗号后是主句。

例4：I visited Paris, where I met my old

4. 标点是边界提示，但不能只看标点。

核心：非限制性定语从句常由逗号隔开；句首 as 从句常到逗号结束；句末定从常到句号结束。

提醒：最终仍要回到先行词和从句谓语，不能只凭逗号机械判断。