定语从句（2）1. 定语从句是历年高考的热点，是必考的语法点。
2. 本讲主要梳理以下知识点：1) 非限制性定语从句，特别是先行词为整个句子的情况；2) 非限制性定语从句中关系代词as 和which的区别；3) 定语从句与其他句式的区别。
一、知识精讲（一）非限制性定语从句1. 非限制性定语从句与先行词的关系不紧密，只是作附加说明，不起限制作用。
2. 非限制性定语从句的关系代词只能用which或who，不能用that，作宾语时，不可以省略。
3. 有时非限制性定语从句所修饰的不是前面的某个词，而是代表整个主句所讲的内容。
4. 非限制性定语从句的主、从句之间往往用逗号隔开，译成汉语时可单独译成一句。
【例句】The old man has a son, who is in the army. 那位老人有一个儿子，他在部队工作。
She comes from Shanghai, which can be told from her accent. 她是上海人，这一点从她的口音就可以判断出来。
例题1Chan’s restaurant on Baker Street, ______ used to be poorly run, is now a successful business.A. thatB. whichC. whoD. where答案：B思路分析：本句的先行词是Chan’s restaurant，在定语从句中作主语，非限制性定语从句不能用that来引导，故选A。
本题同学们看到on Baker Street，可能会误选D，主要是没有判断好先行词在定语从句中作什么成分。
例题2(安徽卷) All the neighbors admire this family, ______the parents are treating their child like a friend.A. whyB. whereC. whichD. that答案：B思路分析：先行词是family, 在从句中作地点状语，要说in the family, 故要选B。
（二）限制性定语从句与非限制性定语从句的区别1. 形式上，非限制性定语从句往往用逗号隔开。
2. 语法上，非限制性定语从句一般不用that引导。
3. 语义上，限制性定语从句与先行词关系紧密，起限定作用，如果去掉了这个定语从句，整个句子就不完整或会改变意思；而非限制性定语从句与先行词关系不是很紧密，对先行词起补充说明或描述的作用。
【例句】I was the only person in our office who was invited.我是办公室里唯一被邀请的人。
（去掉定语从句，意思就不完整）Tom’s father, who is over sixty, still works hard day and night. 汤姆的父亲，已经六十多岁了，仍然日夜努力地工作着。
（who引导非限制性定语从句，整个句子可分成两句来翻译）4. 翻译时，限制性定语从句可译为一句（较短的一般译为“的”字结构）；而非限制性定语从句可译为两句。
【例句】This is the book (that / which) I like best. 这就是我最喜欢的那本书。
Beijing, which has been China's capital for more than 800 years , is rich in cultural and historic relics. 北京是中国八百年之久的古都，它有着丰富的文化和历史遗产。
2. as引导非限制性定语从句既可放在主句之前，也可放在主句之后，用来修饰整个句子。
通常用下列句型：as is known to all, as is said, as is reported, as is announced, as we all know, as I expect 等。
【例句】As I expected, he got the first place again in this mid-term examination. 正如我所预料的那样，他在这次期中考试中又获得了第一名。
China has the largest population in the world, as is known to all. 众所周知，中国拥有世界上最多的人口。
例题（浙江卷）_____ I explained on the phone, your request will be considered at the next meeting.A. WhenB. AfterC. AsD. Since答案：C思路分析：当定语从句放在句首时必须用as引导。
3. as 引导非限制性定语从句时与which的区别He is the only one of the persons who speaks French fluently here.(此句的先行词为the only one 而不是the persons, 是单数，所以定语从句中的谓语动词也要用单数。
) He was one of the students who were praised by the teacher yesterday.（此句中的先行词是the students, 是复数，所以定语从句中的谓语动词要用复数。
）2. 定语从句有时不直接紧靠先行词，中间有一个定语、状语或谓语隔开，叫分隔定语从句。
【例句】There is an expression in his eyes that I can’t understand.在他眼里，有一种我看不懂的神情。
3. 当定语从句中的谓语动词是带介词或副词的固定短语动词时，短语动词的各固定部分不要拆开。
【例句】The sick man whom she is looking after is her father. 她正在照顾的那个病人是她的父亲。
4. 不定代词/ 数词+ of which / whom【例句】故选A。
7. “介词+关系代词”引导定语从句时，确定介词的方法：（1）根据先行词的习惯搭配【例句】They’ll never forget July 1st on which Hong Kong returned to its motherland.他们永远不会忘记7月1日，在这一天香港回到了祖国母亲的怀抱。
1992 is the year in which you were born. 1992年是你出生的年份。
（2）根据定语从句中动词所需的搭配【例句】The school to which I was sent was very large. 我被送去上学的学校非常大。
Hong Kong is the city from which he comes. 他来自于香港。
例题“用介词+which/whom”填空1. At the top of the mountain there is a small house_______________________ we can see the beautiful scenery.（四）定语从句与结果状语从句在定语从句中,若先行词被such 修饰时,关系词要用as, 组成such…as结构。
这个结构与结果状语从句such…that…（如此……以致……）很相似,要注意区别。
若从句中的及物动词后无宾语，就是定语从句，用such…as；否则就是结果状语从句，用such…that。
例题1. I have such a computer ___________you have.2. She is such a kind girl ____________all of us like to make friends with her.答案：1. as 2. that（五）定语从句与习惯句型固定句型：It is the first/second/third time that+ 从句（从句用现在完成时）例题1. It is the first time ______she has been in Shanghai.2. It was the time _______Chinese people had a hard life.答案：1. that 2. when（六）定语从句与单句注意标点符号。
两个单句间用句号，而定语从句的两个句子间用逗号。
例题1. The mother told the lazy boy to wo rk, ____didn’t help.2. The mother told the lazy boy to work. _____didn’t help.3. There are 56 students in our class, most of ____are girls.答案：1. which 2. It 3. whom1. （山东）Whenever I met her, ______ was fairly often, she greeted me with a sweet smile.A. whoB. whichC. whenD. that答案：B思路分析：不管我何时遇见她，她都用甜甜的微笑迎接我，这是常事。
which引导非限制性定语从句，指代前面的句子。
2. （全国II）My friend showed me round the town, ______ was very kind of him.A. whichB. thatC. whereD. it答案：A思路分析：考查非限制性定语从句，这儿的which指代前面整句话的内容。
3. （天津）I travel to the Binhai New Area by light railway every day, _____ do many businessmen who live in downtown Tianjin.A. asB. whichC. whenD. though答案：A思路分析：考查as的非限制性定语从句。
后句句意：我的做法正如/正像生活在天津闹市区的商人一样。
本句为避免头重脚轻，结构经过了调整，主语和谓语颠倒，这点要注意。
which代替的是上句部分或整体的内容，此处没有这个的意思，排除B；C，D句意、结构均不适合，as“正如，正像”符合句意，故选A。
4. （陕西）Gun control is a subject ______ Americans have argued for a long time.A. of whichB. with whichC. about whichD. into which答案：C思路分析：考查定语从句，先行词是Gun control，指物，关系词在从句中作介词的宾语，介词前置，介词与从句动词构成搭配argue about sth.，选C。