一、核心知识点
1. 复合句的分类
| 类型 | 说明 | 例句 |
|---|---|---|
| 名词性从句 | 主语从句、宾语从句、表语从句、同位语从句 | I know that he is right. |
| 定语从句 | 修饰名词或代词 | The man who is standing there is my teacher. |
| 状语从句 | 修饰动词、形容词或整个句子 | I will go if it doesn't rain. |
2. 宾语从句
| 要点 | 说明 | 例句 |
|---|---|---|
| 引导词 | that（可省略）/ if / whether / 疑问词 | I know (that) he is right. |
| 语序 | 陈述句语序（主语在前，谓语在后） | Do you know where he lives?（不是 where does he live） |
| 时态 | 主句现在时，从句任意时态；主句过去时，从句用相应过去时 | He said he would go. |
| if vs whether | whether 可与 or not 连用，if 不能 | I don't know whether or not he will come. |
3. 定语从句
| 关系词 | 指人 | 指物 | 在从句中作成分 |
|---|---|---|---|
| who | ✅ | ❌ | 主语 |
| whom | ✅ | ❌ | 宾语 |
| whose | ✅ | ✅ | 定语 |
| which | ❌ | ✅ | 主语/宾语 |
| that | ✅ | ✅ | 主语/宾语 |
| where | ❌ | ❌ | 地点状语 |
| when | ❌ | ❌ | 时间状语 |
| why | ❌ | ❌ | 原因状语 |
注意： - 关系词在从句中作宾语时可以省略 - that 不能用于非限制性定语从句
4. 状语从句
| 类型 | 引导词 | 例句 |
|---|---|---|
| 时间状语从句 | when, while, as, before, after, since, until, as soon as | I was reading when he came. |
| 条件状语从句 | if, unless, as long as | I will go if it doesn't rain. |
| 原因状语从句 | because, since, as | I stayed at home because it rained. |
| 目的状语从句 | so that, in order that | He studies hard so that he can pass. |
| 结果状语从句 | so...that, such...that | He is so tall that he can reach it. |
| 让步状语从句 | although, though, even though | Although it rained, we went out. |
| 比较状语从句 | than, as...as | He is taller than I am. |
| 地点状语从句 | where | Go where you like. |
二、重点语法规则
规则1：宾语从句的语序
| 类型 | 例句 |
|---|---|
| 陈述句变宾语从句 | He said, "I am tired." → He said (that) he was tired. |
| 一般疑问句变宾语从句 | "Is he right?" → I wonder if/whether he is right. |
| 特殊疑问句变宾语从句 | "Where does he live?" → I know where he lives. |
关键：宾语从句必须用陈述句语序，即"引导词 + 主语 + 谓语"。
规则2：if 引导的条件状语从句（主将从现）
| 主句 | 从句 |
|---|---|
| 一般将来时 | 一般现在时 |
| I will go | if it doesn't rain |
口诀：主将从现，主情从现，主祈从现。
规则3：so...that vs such...that
| 结构 | 用法 | 例句 |
|---|---|---|
| so + 形容词/副词 + that | so 修饰形/副 | He is so tall that he can reach it. |
| so + 形容词 + a/an + 名词 + that | It is so good a book that I like it. | |
| such + a/an + 形容词 + 名词 + that | such 修饰名词 | It is such a good book that I like it. |
| such + 形容词 + 复数名词/不可数名词 + that | They are such good books that I like them. |
规则4：although / though vs but
| 用法 | 例句 |
|---|---|
| although/though 和 but 不能同时用 | Although it rained, we went out. / It rained, but we went out. |
| 但 although/though 可以和 yet/still 连用 | Although it rained, yet we went out. |
三、常见易错点
| 易错点 | 错误 | 正确 |
|---|---|---|
| 宾语从句用疑问语序 | I don't know where does he live. | I don't know where he lives. |
| 关系词选择错误 | The book who I bought... | The book which/that I bought... |
| although 与 but 连用 | Although it rained, but we went out. | Although it rained, we went out. |
| so / such 混淆 | It is so a good book. | It is such a good book. |
| 定语从句中多代词 | The man who he is standing there... | The man who is standing there... |
四、典型例题分析
例题1：宾语从句语序
题目：I am sure ______ the doctor will come soon. A. that B. what C. how
答案：A. that
解析：宾语从句是陈述句，用 that 引导（可省略）。从句用陈述句语序。
例题2：定语从句
题目：The teenagers like the musician ______ different kinds of music. A. who play B. which plays C. who plays
答案：C. who plays
解析：先行词 musician（音乐家）指人，关系词用 who；musician 是单数，从句谓语用 plays。
例题3：条件状语从句
题目：Susan will not arrive at the airport on time ______ she hurries up. A. if B. unless C. because
答案：B. unless
解析：unless = if not，表示"除非"。句意为"除非她快点，否则她不会准时到达机场"。
例题4：so...that
题目：He ran __ fast ____ I couldn't catch up with him. A. so; that B. such; that C. too; to
答案：A. so; that
解析：fast 是副词，用 so 修饰。so...that... 表示"如此……以至于……"。
例题5：定语从句关系词
题目：The teacher ______ has long curly hair is reading books. A. where B. which C. who
答案：C. who
解析：先行词 teacher 指人，关系词在从句中作主语，用 who。
例题6：宾语从句时态
题目：He asked me ______. A. where do I live B. where I lived C. where I live
答案：B. where I lived
解析：主句 asked 是过去时，宾语从句要用相应的过去时态；同时要用陈述句语序。
五、速记口诀
宾语从句口诀：
宾语从句陈述序，主语谓语不分离； 主现从句任意时，主过从句过相应； that 可省要记牢，if whether 表是否。
定语从句口诀：
定语从句修饰名，关系词儿要先行； 指人 who whom whose，指物 which that 行； 地点 where 时间 when，原因 why 要记清。
状语从句口诀：
时间 when while as，条件 if unless； 原因 because since as，目的 so that； 结果 so such that，让步 although though； 主将从现记心间，although but 不连用。