同等学力英语语法之复合句(4)

　　3. 定语从句

　　(1) 定语从句的功用及其一般结构。

　　定语从句在句中做定语，修饰某一名词或代词。从句所修饰的词叫先行词，定语从句必定是要放在先行词之后的。定语从句由关系代词或副词引导，其中关系代词有who，whom，whose，which和that。关系副词有when，why，where等。

　　例如：

　　We went to the park which / that we often visited. 我们去了我们常去的公园。

　　I can never forget the day when I began my studies in Beijing University. 我永远也忘不了我进入北京大学的那天。

　　The wine，which was in the cellar，was all ruined. 酒窖里的酒都变质了。

　　(2) 定语从句的种类。

　　定语从句可分为限制性定语从句和非限制性定语从句。

　　①限制性定语从句：从句和主句中的被修饰词关系密切，如去掉从句，主句的意思就不完整或者逻辑上不成立。它的作用是通过对特定对象的限定，起到区别特定对象与其他对象的作用。引导从句的关系代词如果在从句中做宾语，可省略。在书写时，主句和从句之间不需逗号分开。

　　例如：

　　A man who doesn’t try to learn from others can’t hope to achieve much. 一个不愿意向别人学习的人是不会有很大进步的。

　　②非限制性定语从句：非限制性定语从句只对所修饰的词起附加说明或进一步描述、补充的作用，有一定的独立性，去掉之后，其他部分仍然可以成立，从句和主句之间常用逗号分开。所用的关系代词和限制性定语从句基本相同，但不能用关系代词that来引导。

　　例如：

　　The most important form of energy is electrical energy，which is widely used in our everyday life. 最重要的一种能源形式是电能，它在我们的日常生活中得到了广泛使用。

　　I have many foreign friends，some of whom are Russian. 我有很多外国朋友，其中有几位来自俄罗斯。

　　非限制性定语从句除了修饰主句的名词或代词外，还可以修饰整个句子。这时从句中的谓语动词用单数第三人称，并且用 which来引导。例如：

　　The sun heats the earth，which makes it possible for plants to grow. 太阳给地球热量，这使得地球上的植物能够生长。

　　(3) 关系代词和关系副词。在句中关系代词与关系副词有两个作用：第一，指代主句中的一个名词或代词(起修饰、限定作用);第二，在从句中承担一定的语法成分。关系代词在从句中做主语、宾语，关系副词在从句中做状语。

　　①做主语时需要注意的是，关系代词在从句中做主语，其谓语动词在人称和数上必须与先行词保持一致。例如：

　　Do you know the girl who is talking with the teacher?你认识正在和老师谈话的那个女孩吗?

　　Wei Fang is one of the students who have studied Japanese before. 卫放是几个以前学过日语的学生之一。

　　该句的先行词是students，所以关系代词who后面的谓语动词用复数形式。

　　②做宾语。关系代词whom，that，which在从句中做宾语，在非正式文体中可以省略。例如：

　　This is the girl(whom)you’ve been looking for. 这就是你们要找的那个女孩。

　　Such people as you describe are rare nowadays. 你所描述的那些人现在很少见了。

　　③做定语。关系代词whose在从句中用做定语。例如：

　　Thomas Edison is a great inventor whose fame is world-wide.

　　The Smiths，whose house had been destroyed in the explosion，were given rooms in the hotel.

　　④做状语。关系副词when，where，why在定语从句中分别做时间状语、地点状语和原因状语。当然，先行词相应地也应分别是表示时间、地点、原因的名词。例如：

　　We may discuss the question when we meet again.

　　That is the place where the famous poet was born.

　　That he is too busy is the reason why he can’t do it now.

　　在做题时，要具体情况具体分析。

　　(1) 关系代词who指人，在从句中做主语(有关从句中的主谓一致已在前面提到，请注意);whom指人，在从句中做宾语，在限制性定语从句中常常省略;whose指人，做定语;which指物，在从句中做主语或宾语，做宾语时常可省略;that可指物或人，在从句中可做主语或宾语，指物时用法和which大致一样。

　　1)which做主语。例如：

　　例1. Every intellectual revolution which has ever stirred humanity into greatness has been a passionate protest against inert ideas.

　　例2. A dictionary is a book which gives the meaning and usage of words.

　　2)which做宾语。例如：

　　例1. That is the house in which Mr. Wang lives.

　　例2. This is the novel which Mr. Zhang mentioned this morning.

　　3)that的用法。(注意它在限制性定语从句中指物或指人，指物时和which差不多，但不能做从句中的介词宾语)

　　例1. Could you lend me the novel about which you were talking the other day?

　　例2. All that glitters is not gold.

　　(2) 关系副词when，where，why在从句中均做状语。

　　(3) whom，which在定语从句中充当介宾时，介词的位置一般来讲，如果是含有介词的短语动词，介词仍要在动词之后，而which，whom的位置不变。但如果介词短语独立于从句谓语动词之外，这时介词应置于which，whom之前。

　　例如：

　　例1. While still a young boy，Bizet knew how to play the piano well and as he grew older，he wrote operas，the most famous of which is Carmen.

　　例2. Your carelessness，which we have put up with for a long time，is beginning to annoy the director.

　　例3. This rule is out of date. It is the thing which the government should do away with.

　　(4) 关系代词who，that亦可用做现在分词或过去分词的宾语(who指人，that指物或人)，但分词必须放在从句之末，而who在非正式文体中可省略。

　　(5) 关系代词which的特殊用法。

　　which的先行词有时不是一个单词，而是前面整个主句或主句的一部分所表达的概念，which在这时意同 and this。例如：

　　例1. They have invited me to take part in the party，which is very kind of them.

　　例2. Wei Fang helped me with my English，which was kind of her.

　　(6) that和which均指物时，一般没什么区别，但在一些特殊情况下不可混用，而这些特殊情况往往是考试的重点。

　　在下列情况下，一般只用that。

　　1)先行词是all，everything，nothing，something，anything，little等不定代词。例如：

　　例1. All that you have to do is to make a clean copy of the draft.

　　例2. Everything that the teacher said seemed quite reasonable if you had mastered the main meaning of his words.

　　2)先行词为形容词最高级序数词修饰时(that也可省略)。例如：

　　例1. This is the first thing that I want to say.

　　例2. This is the best step that can be taken.

　　还有以“as”引导的定语从句，多和such连用。例如：

　　例1. Such people as described in the novel are rare nowadays.

　　例2. Hearing the news that her husband received a heavy sentence，she left with a weight on her mind such as she had never had before.

　　例3. She opposed our idea，as could expected.

本文选自新东方在线论坛。