概览

在单句的部分，我们已经讨论了句子的组成元素。除了诸如名词、形容词和副词等基本元素外，为了表达与动作相关的概念，我们引入了动状词。同时，动词时态很好的处理了时间的问题，而语气则是让我们可以表达真与假。

但有一个重要的问题是，目前我们只能使用单词或片语，这会极大的限制我们精确传递信息的能力。所以我们引入了复合句来处理这个问题。注意到动词或动词片语具有处理时态、语气、人称的能力，且对动作本身的表达扩展实际上是基于修饰它的副词而实现的，所以并没有动词子句的说法。

这篇文章我们会讨论英语中比较重要的三种子句：名词子句、副词子句以及形容词子句（关系子句）。区分的依据是子句在主句中承担的角色。我们将子句作为一个整体，依照其角色处理其位置。例如一个名词子句在句子中作为名词使用，而名词在单句中可以作为主词、及物动词的受词、补语、介系词受词以及同位格使用。所以名词子句也应当这样使用。

名词子句

由连接词引导的名词子句，在主句中作为名词使用。与普通名词一样，名词也表达一个概念。这个概念可以是一段陈述或询问，所以名词子句可以由直述句或疑问句修改而来。

构造名词子句

如上所述，名词子句可以由直述句或疑问句改写而来。需要外加连接词。

直述句

在原本的句子前面加一个单独的、无意义的从属连接词以表示子句表达的那句话或那件事，由此便构造了一个名词子句。

• He didn’t take the money. + I believe that.
  • I believe that he didn’t take the money.

疑问句

疑问句有两种类型，询问具体信息的 information questions 和回答是否的 Yes/No questions。对于前者，我们可以直接使用疑问词来充当连接词，即可构成一个名词子句。但注意如果疑问词在子句中不是主词时，需要还原句子语序。而对于后者，我们需要使用 whether/if 来引导子句，构成名词子句。下面是一些例子。

• Where did he keep the money? + He never revealed the question.
  • He never revealed where he kept the money.
• Is it going to rain soon? + By looking at the sky, I can tell the question.
  • By looking at the sky, I can tell whether it is going to rain soon.

使用名词子句

如前所述，名词子句本质上是使用句子表达复杂概念，在使用时应当和使用一个普通名词一样。也就是说，我们可以在以下 5 种地方使用名词子句：

1. 主词
2. 及物动词受词
3. 介系词受词
4. 补语
5. 名词同位格

在使用时，因为直述句改写时添加的 that 无意义，所以可以省略。而疑问句的引导词实际表达了问题的询问目的，所以不可以省略，否则句意会模糊。

有一个经验性的技巧是，如果主句的限定动词和子句的限定动词间存在一个主词，那么我们往往可以省略那个连接词。因为即使这样，我们在分析句子结构时也不会误认为句子里有两个限定动词。

1. Something is an undeniable fact. + The suspect has a strong alibi.
   • That the suspect has a strong alibi is an undeniable fact.
   • It is a undeniable fact that the suspect has a strong alibi.
2. Where is he hiding now? + The question is a big mystery.
   • It is a big mystery where he is hiding now.
3. Many people believe something. + One’s zodiac sign determines one’s character.
   • Many people believe that one’s zodiac sign determines one’s character.
4. The question why the dinosaurs died out may never be answered.
5. My response depends on the question. + What did he really meant by that?
   • My response depends on what he really meant by that.

有一个特例是，普通名词可以直接放在介系词后面作为受词。而由直述句改写而来的名词子句会使用 that 引导，但这种名词子句不能直接放在介系词后面，否则是语法错误。为了处理这个问题，我们可以将原本的主要子句改写为同位格。

1. His response dwells on the fact. + I owe him a favor.
   • His response dwells on the fact that I owe him a favor.

评论子句与引用

评论子句指的是英语中的一些口头禅，在口语中经常使用，但我们一般不将其作为一个从属子句对待。

• This trick, you know, will never work.

直接引用一句话时，需要使用双引号。间接引用相当于改写为自己的话，所以不需要双引号。

• The guard said, “The road is closed.”
• The guard said that the road is closed.

副词子句

副词子句由有意义的连接词引导，该连接词表达逻辑关系，从而构成整个副词子句。子句是副词类，在主句中用来修饰动词、形容词和副词等。

在单句中，副词用于描述时间、频率、范围、语气、程度等概念。所以当构造一个副词子句时，就需要在连接词上体现出这种逻辑关系。

构造副词子句

与名词子句一样，副词子句也可由直述句或疑问句改写而来。需要外加连接词。

直述句

由直述句构造副词子句时，有以下两种方法：

1. 使用如 because/although/if/as/when/where 这类表达原因、让步、条件、状态、时间、地方的连接词
2. 使用 so … that / such … that / in that / in order that 等句型

下面是一些例子。每组第一句是名词子句，而第二句是副词子句。

1. I believe that ghosts are real.

2. I believe that, because I have seen one with my own eyes.

3. He said sincerely that he was sorry.

4. He said it so sincerely that his wife forgave him right away.

另外需要注意的是，when/where 也可以作为关系词引导关系子句。所以需要特别注意这种子句是在表达动作发生的时间地点（副词子句），还是在详细阐述一个先行词（关系子句）。

疑问句

如前所述，疑问句分为 information questions 和 Yes/No questions。

对于前者，我们在疑问词前加 no matter 或在疑问词后加 -ever 字尾作为连接词，同时还原句子语序，即可构造出副词子句。对于后者，我们使用 whether 作为连接词，同时还原句子语序，也可构造出副词子句。

注意 whether 在名词子句中解释为是否，而在副词子句中解释为不论。

1. Where the criminal is hiding is anybody’s guess. 名词子句

2. No matter where the criminal is hiding, the police is going to get him.

3. Wherever the criminal is hiding, the police is going to get him.

4. Whether he’s still alive (or not) is difficult to say. 名词子句

5. Whether he’s still alive (or not), I’m not going to marry anyone else.

6. No matter he’s still alive (or not), I’m not going to marry anyone else.

使用现在式代替未来式

我们曾经提到过，在表达时间、条件的副词子句中，需要使用现在式代替未来式。但更好的理解是该副词子句已经表达了假设的逻辑，而现代文法删除了所谓的现在式，转而将其阐述为不确定语气。也就是说我们没必要在副词子句中再使用不确定语气。

1. He didn’t tell me when he bought the house. 名词子句
2. He didn’t tell me the price when he bought the house.
3. I can’t remember if turned off the gas or not.
4. I have to go back if I didn’t turn off the gas.

常用的副词子句连接词

因为副词子句的连接词需要表达逻辑，所以不像名词子句或关系子句那样只有固定的几个连接词。下面列出一些常用的连接词，积累这种词汇有助于清晰的表达逻辑。

关系子句

关系子句，使用关系词作为连接词，在主句中做形容词，所以又被称为形容词子句。换句话说，关系子句是对先行词的进一步精确描述。

我们提到过名词子句和副词子句中的连接词都是在构造子句时添加的。而关系子句不同，我们需要将主句和子句中的重复点改写为关系词，才能构建出关系子句。这个重复点为名词类。由此，我们可以推导出：

1. 两个句子合并为关系子句的前提是有一个重复元素，我们将主句中的重复点称为先行词，而子句中的重复点则被改写为关系词。
2. 关系词由子句的重复点改写而来，所以需要遵循其位置导致的词态变化。

当主句的先行词为人、物或对应代名词时，我们使用关系代名词作为连接词。如果关系子句具有指示的作用，我们会省略那个代名词。另外，根据先行词的种类，连接词还会有一些变化。

1. 先行词为模糊、无意义的词如 anybody/something 等，使用复合关系代名词
2. 先行词描述时间、地点、方法状态或原因等，使用关系副词

下面我们讨论先行词的这三种场景。

关系代名词

先行词或者说两个句子的重复点是人、物或对应的代名词，我们使用关系代名词构建关系子句。这个子句作为形容词使用，进一步详细描述人、物或对应的代名词，也就是作为形容词使用。

另外的，根据先行词所代表的重复点在子句中的位置，我们需要使用关系代名词的不同变化，可参考：

当关系子句具有指示功能时，我们通常可以使用由指示代名词衍生出的关系代名词 that 代替。如果语义清楚，不会出现两个限定动词的歧义，我们就可以省略这个关系代名词 that。

先行词代表的重复在带子句中为受格时，关系代名词需要使用受格。但如果代名词不在介系词之后或脱离了原来的受词位置，则可以使用原始形态即 who / which.

先行词为人

当先行词为人时，我们使用 who 类关系代名词。需要再一次提示的是，关系代名词的形式取决于那个重复点在子句中的角色，因为关系代名词替代了那个词。

1. People shouldn’t throw stones. + They lives in glass houses.
   • 代名词原本是主词
   • People who/that lives in glass houses shouldn’t throw stones.
2. Jack is a man. + I trust the man completely.
   • 代名词原本是受词
   • Jack is a man whom/who/that I trust completely.
3. Jack is a man. + You should talk to him.
   • 代名词原本是介系词的受词
   • Jack is a man who/whom/that you should talk to him.
   • Jack is a man to whom you should talk.
4. After the stroke, John is not the man. + He used to be the man.
   • 代名词原本是补语
   • After the stroke, John is not the man who/that he used to be.
5. Jack is a man. + I trust his judgment.
   • 代名词原本是所有格
   • Jack is a man whose judgment I trust.

先行词为事、物

当先行词为事、物时，我们使用 which 类关系代名词。同样的，对于具有指示作用的关系子句，可以使用 that 代替具体的关系代名词。在句意结构清楚的前提下，也可省略 that。

1. I like movies. + The movies make me think.
   • 代名词原本是主词
   • I like movies which/that make me think.
2. The movie was excellent. + I saw the movie last night.
   • 代名词原本是受词
   • The movie which/that I saw last night was excellent.
3. My favorite movies are those. + All ends well in those movies.
   • 代名词原本是介系词受词
   • My favorite movies are those in which all ends well.
4. The name is a really odd one. + John calls his dog the name.
   • 关系代名词原本是补语
   • The name which John calls his dog is a really odd one.
5. I saw a mountain. + Its top was completely covered in snow.
   • 关系代名词原本是所有格，可借用 whose，或使用无生物的 of which
   • I saw a mountain whose / of which the top was completely covered in snow.
6. You can marry any daughter of mine. + You like that daughter.
   • 关系代名词代表的是限定词，即使先行词是人，也需要使用 which
   • You can marry any daughter of mine which / that you like.

另外，整个主要子句也可以作为先行词，此时我们可以用关系代名词 which 引导子句，并用逗号和主句隔开。

1. The whole house was overrun with ants, which was rather weird.
2. The whole house was overrun with ants, which were rather weird.

但要注意这并不意味着用逗号隔开的子句都是以主句为先行词的关系子句。例如上句 2，限定动词为 were，也就是说该子句对应的先行词为 ants。

复合关系代名词

如果先行词是模糊、无意义的词如 anybody/something 等，可以省略先行词并将关系代名词改写为复合关系代名词。从语法上说，此时关系子句兼具先行词与修饰先行词的形容词子句两种角色，所以该关系子句升格为名词子句。

复合关系代名词有：what / whatever / whichever / whoever / whomever.

1. You mustn’t let something bother you. + He said something.

   • You mustn’t let something that he said bother you.
   • You mustn’t let what he said bother you.

2. Anything may be used against you in court. + You say anything now.

   • Anything that you say now may be used against you in court.
   • Whatever you say now may be used against you in court.

3. Any day is fine with me. + You choose that day.

   • Any day which you choose is fine with me.

   • Whichever you choose is fine with me.

4. Any person will win 1,000 dollars. + The person reaches the mountaintop first.

   • Any person who reaches the mountaintop first will win 1,000 dollars.
   • Whoever reaches the mountaintop first will win 1,000 dollars.

5. Any person qualifies for the job. + You see the person in this room.

   • Any person whom you see in this room qualifies for the job.
   • Whoever / Whomever you see in this room qualifiers for the job.

关系副词

当主句中的名词先行词描述时间、地点、方法状态或原因等概念，作为形容词子句的关系从句就需要对这个概念做进一步解释，这意味着在子句中的重复元素是作为副词而使用的。这种时候我们需要使用关系副词引导子句。我们可以将时间副词与对应的关系副词列出：

因为 when 和 where 既可以引导关系子句，也可以引导副词子句，所以需要细致的分析句子结构。

1. The earthquake hit at a time. + Most people were sound asleep then.
   • The earthquake hit at a time when / that most people were sound asleep.
2. The artist lived in a place. + It was impossible to work there.
   • The artist lived in a place where / that it was impossible to work.
3. I never found out the way. + He escaped so.
   • I never found out the way how / that he escaped.
4. The man didn’t explain the reason. + He wanted a divorce for a reason.
   • The man didn’t explain the reason why he wanted a divorce.

注意 when / where 引导的关系子句在被逗号隔开后，一般也不再具备指示功能，只能当作补充说明。

1. Written history of America began in 1492, when Christopher Columbus arrived with his ships.
2. The civilization of ancient Egypt was born along the Nile, where the soil was kept fertile by annual flooding.

省略导致的特殊句式

我们在实际中会遇到处于主词补语位置的关系子句或所谓的准关系代名词。但这些并不是所谓的特例，而是标准的关系子句省略部分成分后的结果。

首先关系子句不可能作为主词补语。因为关系子句是形容词，而主词补语在语法上与主词对等，也就是说可以互换而不破坏句子结构。很显然单独的形容词不可能作为主词。

导致主词补语位置的关系子句的原因是，when / where 引导的关系从句原本是对先行词的解释，但先行词往往没有什么具体含义，或是子句可以暗示出先行词要表达的内容。所以我们常常像使用副词子句一样，使用这样的关系从句。

1. This station is the station. + I get off at this station.
   • This station is the station where I get off.
   • This is where I get off.
2. Thanksgiving is the time. + American families get together at this time.
   • Thanksgiving is the time when American families get together.
   • Thanksgiving is when American families get together.

其次是所谓的准关系代名词。具体为 than / as / but 这三个。但实际上前二者原本是比较句式中的连接词，而后者为对等连接词。这样构造出的句子需要保证两个子句平行对称，这会导致非常多的重复元素。所以我们会省略大部分内容，而得到的句子就会看起来像是关系从句一样。

1. The theory raised more questions than it answered.
   • The theory raised more question than the question that it answered.
   • that 引导的是真正的关系从句
2. Her performance is as good as can be expected.
   • Her performance is as good as the performance that can be expected.
3. There is no one but knows this.
   • There is no one but the one knows this.

分裂句

分裂句指的是使用 it is … that … 的句型改写一个单句，结果是得到一个一主一从的结构。这种句型用于强调，且可强调原单句中的主词、受词、时间副词、地方副词。

• Your friend bought a can of peaches at a 7-11 last night.
  1. It was your friend that/who bought a can of peaches at a 7-11 last night.
  2. It was a can of peaches that/which your friend bought at a 7-11 last night.
  3. It was a 7-11 that/where your friend bought a can of peaches last night.
  4. It was last night that/when your friend bought a can of peaches last night.

而当我们需要强调动词时，需要使用 what one is (to) V 的句型。

1. What your friend did at a 7-11 last night was (to) buy a can of peaches.
2. All (that) your friend did at a 7-11 last night was (to) buy a can of peaches.

易于混淆的连接词

在讨论三种子句时，有一些连接词频繁的出现，这可能会导致混淆。所以在这里做一个关于连接词的总结。

wh-

wh- 的词可以分为：

1. 关系词，引导关系子句
2. 疑问词，引导名词子句
3. 从属连接词，引导副词子句

关系词

关系词包括关系代名词 who/which 和关系副词 when/where/how/why。引导形容词子句，修饰先行词。

1. My father is a man who always keeps his word. 关系代名词
2. I’ll never forget my high school days, when life seemed so simple. 关系副词

疑问词

疑问词包括 who/which/what/when/where/how/why ，引导由疑问句改写而来的名词子句。

1. Who stole the money will be revealed soon.
2. Tell me which of the two designs is prettier.

外加的从属连接词

这种连接词包括 when/where。引导副词子句，修饰动词的时间和地点。

1. The game ended when he hit a homerun.
2. The ship is to boldly go where none has gone before.

wh-ever

分为：

1. 复合关系代名词，引导名词子句
2. 从属连接词，引导副词子句

复合关系代名词

可认为是先行词简化后的结果，引导名词子句。

1. What/The thing that he says can’t be true.
2. Whatever/Anything that he says can’t be true.
3. I’ll hire whomever/anyone that you recommend.

从属连接词

相当于在疑问词前加 no matter，表示让步。

1. Whoever/No matter who told you that story, don’t believe it.
2. There will be difficulties whichever way/no matter which way you go.

that

可以分为：

1. 名词子句从属连接词
2. 副词子句从属连接词
3. 关系词

引导名词子句的从属连接词

直述句加单独、无意义的连接词 that，引导名词子句

• Are you sure that everything is all right?

引导副词子句的从属连接词

直述句加 so that/such … that/in order that/in that 等有意义的连接词，引导副词子句。

1. He started work early so that he could finish on time.

关系词

改写自关系代名词 who/which 以及关系副词 when/where/how/why 等。引导的子句没有用逗号与先行词隔开，是具有指示功能的关系子句（形容词子句）

1. He’s the man that/whom I told you about.
2. What’s the best movie that/which you’ve ever seen?