从句

简介

从句（Subordinate Clause）是 不能独立成句、必须依附主句存在的结构。

从句本身包含 主语 和 谓语，但充当主句的某个成分。

按 语法功能 可分为 $3$ 大类：

• 名词性从句：在主句中充当 名词 的位置（主语、宾语、表语、同位语）。
• 形容词性从句：又称 定语从句，修饰名词或代词。
• 副词性从句：又称 状语从句，修饰动词、形容词、副词或整个主句。

名词性从句

名词性从句（Nominal Clause）在主句中占据名词的句法位置。

按功能可分为 $5$ 种：主语从句、宾语从句、表语从句、宾语补语从句、同位语从句。

引导词

引导词类型	常见引导词
从属连词	that, whether, if
连接代词	who, whom, whose, what, which
连接副词	when, where, why, how

提示

引导词的选择规则：

• that：陈述意义，不充当从句成分。
• whether / if：「是否」之意，if 只用于宾语从句。
• wh- 类：表 疑问意义，在从句中充当成分。

主语从句

主语从句 充当主句的主语。

直接置于句首，或用 形式主语 it 替代，真正从句后置。

Example

• That he is honest is well-known.
• It is well-known that he is honest. (更常用)
• What he said surprised us.

形式主语句型常见结构：

句型	示例
It is + 形容词 + that	It is clear that he is right.
It is + 名词 + that	It is a pity that you can't come.
It seems / happens that	It seems that he is angry.

宾语从句

宾语从句 充当 动词 或 介词 的宾语。

Example

• I know that he is right.
• I wonder whether she will come.
• I am sure of what he said.

引导词 that 在宾语从句中通常可省略，但下列情况不可省略：

• 多个并列宾语从句中的 第二个及之后。
• 主句和从句之间隔有其他成分。
• that 引导的主语从句、表语从句、同位语从句。

Example

• He said that he was tired and that he wanted to rest.

时态呼应

主句为 过去时态 时，宾语从句通常使用 相应的过去时态。

主句	从句变化	示例
一般现在	一般过去	He said he was ill.
现在完成	过去完成	He said he had finished.
一般将来	过去将来	He said he would come.

提示

从句陈述 客观真理、自然规律、习惯动作 时，不受主句时态影响，始终用 一般现在时态。

Example

• The teacher said the earth goes around the sun.

表语从句

表语从句 充当主句的表语，置于 连系动词 之后。

Example

• The truth is that he lied.
• The question is whether we should go.
• This is what I want.

宾语补语从句

宾语补语从句 充当宾语补语，常见于 make, find, think, consider 等动词后。

Example

• We considered it strange that he didn't come.
• I find it difficult to understand him.

同位语从句

同位语从句 跟在 抽象名词 后，对该名词进行 解释或说明。

常接同位语从句的名词：fact, news, idea, belief, hope, suggestion, doubt, opinion, …

Example

• The news that he won the prize spread quickly.
• I have no doubt that he is honest.

同位语从句 vs. 定语从句

类型	引导词 that 在从句中作用	示例
同位语从句	不作成分（解释名词）	The fact that he lied is clear.
定语从句	充当从句成分（修饰名词）	The fact that he told us is clear.

形容词性从句

形容词性从句（Adjective Clause），又称 定语从句（Relative Clause），用于修饰 名词 或 代词。

被修饰的词称为 先行词（Antecedent）。

引导词

引导词类型	常见词	在从句中的作用
关系代词	who, whom, whose, which, that, as	充当主语、宾语、定语
关系副词	when, where, why	充当状语

引导词	适用先行词	在从句中作用	示例
who	人	主语、宾语	The man who came is my uncle.
whom	人	宾语	The man whom I met is my uncle.
whose	人 / 物	定语	The boy whose father is a doctor.
which	物	主语、宾语	The book which I read.
that	人 / 物	主语、宾语	The man that came / The book that I read.
when	表时间名词	时间状语	The day when I met him.
where	表地点名词	地点状语	The place where I live.
why	reason	原因状语	The reason why I came.

限制性 vs. 非限制性

类型	特征	示例
限制性定语从句	修饰先行词不可缺，无逗号	The boy who is reading is my brother.
非限制性定语从句	补充说明，用逗号隔开	My father, who is a doctor, is busy.

提示

非限制性定语从句 不能用 that 引导。

关系代词 that 与 which 的选择

下列情况只能用 that：

• 先行词被 最高级、序数词、all, every, no, any, only 等修饰。
• 先行词为 不定代词（something, anything, nothing, all, everything）。
• 先行词同时包含 人和物。

Example

• This is the best book that I have ever read.
• All that glitters is not gold.

下列情况只能用 which：

• 引导 非限制性定语从句。
• 介词后置时（in which, of which）。

介词 + 关系代词

介词可前置或后置。

• 前置：only with whom, in which 等。
• 后置：whom...with, that...in 等。

Example

• The man with whom I spoke is my uncle.
• The man whom I spoke with is my uncle.
• The man that I spoke with is my uncle. (介词后置，可用 that)

副词性从句

副词性从句（Adverbial Clause），又称 状语从句，用于修饰 动词、形容词、副词 或 整个主句。

按语义可分为 $9$ 类，引导词详见 连词。

时间状语从句

引导词：when, while, as, before, after, since, until / till, as soon as, once, …

Example

• I will call you when I arrive.
• He waited until she came back.

提示

时间状语从句中，主将从现：主句用 将来时态，从句用 一般现在时态 替代将来时态。

Example

• I will leave when he comes. when he will come

地点状语从句

引导词：where, wherever。

Example

• Sit wherever you like.
• I will go where you go.

原因状语从句

引导词：because, since, as, for, now that, seeing that。

Example

• I stayed home because it rained.

目的状语从句

引导词：so that, in order that, lest, for fear that。

从句常用 may, might, should + 动词原形。

Example

• Speak loudly so that everyone may hear.

结果状语从句

引导词：so...that, such...that, so that。

Example

• He is so tired that he can't walk.
• It is such a heavy box that I can't lift it.

条件状语从句

引导词：if, unless, provided that, as long as, in case。

主将从现：主句将来时态，从句一般现在时态。

Example

• I will go if it doesn't rain.

让步状语从句

引导词：though, although, even if, even though, while, whereas, no matter wh-, whatever, however, …

Example

• Although it is raining, we'll go.
• However hard he tries, he can't succeed.

方式状语从句

引导词：as, as if, as though。

as if / as though 可用 虚拟语气（详见 动词语气）。

Example

• Do as I say.
• He talks as if he knew everything.

比较状语从句

引导词：than, as...as, the more...the more。

Example

• He is taller than I am.
• The harder you work, the more you gain.

思维导图