英语语法基础知识——定语从句

定语从句及相关术语 1.定语从句：定语从句是由关系代词或关系副词引导的从句，其作用是作定语修饰主句的某个名词性成分，相当于形容词，所以又称为形容词性从句，一般紧跟在它所修饰的先行词后面。 2.关系词：引导定语从句的关联词称为关系词，关系词有关系代词和关系副词。关系代词有that, which, who, whom, whose, as等；关系副词有where, when, why等。关系词常有3个作用：1，引导定语从句。2，代替先行词。3，在定语从句中担当一个成分。 注：关系代词有主语、宾语之分。一般whom作为宾语。 4.定语：定语用来限定、修饰名词或代词的，是对名词或代词起修饰、限定作用的词、短语或句子，汉语中常用„……的‟表示。主要由形容词担任。此外，名词，代词，数词，分词，副词，不定式以及介词短语也可以来担任，也可以由一个句子来担任．单词作定语时通常放在它所修饰的词之前，作前置定语。短语和从句作定语时则放在所修饰的词之后，作后置定语。

（一） 限定性定语从句 一、关系代词（在句中作主语、宾语或定语） 1. that既可代表事物也可代表人，which代表事物；它们在从句中作主语或宾语，that在从句中作宾语时常可省略关系词，which在从句中作宾语也可以省略。[eg：this is the book （which）you want。]而且，如果which在从句中作“不及物动词＋介词”的介词的宾语，注意介词不要丢掉，而且介词总是放在关系代词which的前边，但有的则放在它原来的位置 2. which作宾语时，根据先行词与定语从句之间的语义关系，先行词与which之间的介词不能丢 3. 代表物时多用which，但在带有下列词的句子中用that而不用which，这些词包括当先行词是anything, everything, nothing , none等不定代词时，或者是由every, any, all, some, no, little, few, much等修饰时等，这时的that常被省略 还有先行词前有序数词或形容词最高级修饰时,或先行词就是序数词或最高级时.以及先行词中既有人又有物时.还有句中前面有which时,都只能用that 4. who和whom引导的从句用来修饰人，分别作从句中的主语和宾语，whom作宾语时，要注意它可以作动词的宾语也可以作介词的宾语 5. whose是关系代词，修饰名词作定语，相当于所修饰成分的前置所有格.它引导的从句可以修饰人和物, 当它引导的从句修饰物体时, 可以与 of which 调换,表达的意思一样。

二、关系副词（在句中作状语） 关系副词=介词+关系代词 why=for which where=in/ at/ on/ ... which (介词同先行词搭配) when=during/ on/ in/ ... which (介词同先行词搭配) 1. where是关系副词，用来表示地点的定语从句。 2. when引导定语从句表示时间［注］值得一提的是，表示时间“time"一词的定语从句只用when引导，有时不用任何关系代词，当然也不用that引导。 By the time you arrive in London, we will have stayed there for two weeks. I still remember the first time I met her. Each time he goes to business trip, he brings a lot of living necessities, such as towels, soap, toothbrush etc。 3. 当从句的逻辑主语是some, any, no, somebody, anybody, nobody, something, anything, everything或nothing时，常用there is来引导 There is somebody here who wants to speak to you. 这里有人要和你说话。

（二）非限定性定语从句 非限定性定语从句的作用是对所修饰的成分作进一步说明，通常是引导词和先行词之间用逗号隔开，将从句拿掉后其他部分仍可成立 1. which引导的非限定性定语从句来说明前面整个句子的情况或主句的某一部分 2.当先行词是专有名词或物主代词和指示代词所修饰时，其后的定语从句通常是非限制性的，例如： Charles Smith, who was my former teacher, retired last year. 查理·史密斯去年退休了，他曾经是我的老师。 My house, which I bought last year, has got a lovely garden. 我去年买的的那幢房子带着个漂亮的花园。 This novel, which I have read three times, is very touching. 这本小说很动人，我已经读了三遍。 3.非限制性定语从句还能将整个主句作为先行词, 对其进行修饰, 这时从句谓语动词要用第三人称单数，例如： He seems not to have grasped what I meant, which greatly upsets me. 他似乎没抓住我的意思，这使我心烦。 Liquid water changes to vapor, which is called evaporation. 液态水变为蒸汽，这就叫做蒸发。 4. 有时as也可用作关系代词 5. 在非限定性定语从句中，不能用关系副词why和关系代词that，而用who, whom代表人，用which,whose代表事物.；

（三）关系代词引导的定语从句 1.who指人在从句中做主语 (1) The boys who are playing football are from Class One. (2) Yesterday I helped an old man who lost his way. 2. whom指人，在定语从句中充当宾语，常可省略。（注：who和whom已无太大区别，可以通用。） (1) Mr. Liu is the person (whom) you talked about on the bus. (2) Mr. Ling is just the boy whom I want to see. (3) The man who/whom you met just now is my friend. 注意：关系代词whom在口语和非正式语体中常用who代替，可省略。 如果在从句中做宾语,就用whom或who.比如: He is the man whom/who I talk to. 如果是在从句中作主语就只能用who.比如: He is the man who has an English book. 3.which指物，在定语从句中做主语或者宾语，做宾语时可省略 (1) Football is a game which is liked by most boys. (2) This is the pen (which) he bought yesterday. 4. that指人时，相当于who或者whom；指物时，相当于which。 在定语从句中做主语或者宾语，做宾语时可省略。 (5) The number of the people that/who come to visit the city each year rises one million. (6) Where is the man that/whom I saw this morning? 5. whose通常指人，也可指物，在定语从句中做定语 (1) He has a friend whose father is a doctor. (2) I once lived in a house whose roof has fallen in.whose指物时，常用以下结构来代替 (3) The classroom whose door is broken will soon be repaired. (4) The classroom the door of which is broken will soon be repaired. (5) Do you like the book whose color is yellow? (6) Do you like the book the color of which is yellow?

（四）注意 介词+关系代词引导的定语从句关系代词在定语从句中做介词宾语时 从句常由介词+关系代词引导 (1) The school (that/which) he once studied in is very famous. (2) The school in which he once studied is very famous. (3) Tomorrow I will bring here a magazine (that/which) you asked for. (4) Tomorrow I will bring here a magazine for which you asked. (5) We‟ll go to hear the famous singer (whom/that/who) we have often talked about. (6) We‟ll go to hear the famous singer about whom we have often talked. 注意：1. 含有介词的动词短语一般不拆开使用，如：look for, look after, take care of等 (1) This is the watch which/that I am looking for. (T＝正确) (2) This is the watch for which I am looking. (F＝错误) 2. 若介词放在关系代词前，关系代词指人时用whom，不可用who或者that；指物时用which，不能用that；关系代词是所有格时用whose (1) The man with whom you talked is my friend. (T) (2) The man with that you talked is my friend. (F) (3) The plane in which we flew to Canada is very comfortable. (T) (4) The plane in that we flew in to Canada is very comfortable. (F) 3. “介词+关系代词”前可有some, any, none, both, all, neither, most, each, few等代词或者数词 (1) He loved his parents deeply, both of whom are very kind to him. (2) In the basket there are quite many apples, some of which have gone bad. (3) There are forty students in our class in all, most of whom are from big cities.