主句省略先行词 定语从句 That was (the time) when he lived there That's (the reason) why he spoke. It is (the place) where I was born 2) when, where, why 可被\或\介词 + which\取代的情况。 ① 在现代英语中，尤其在口语中，the day/year/time/moment when中的when可用that或恰 当的\介词+ which\取代。
I remember the day when/that the heat wave started I remember the day on which the heat wave started ② the place where 用 the place that 或\介词 + which\取代。
This is the place where/that we used to live. This is the place in which we used to live. ③ the reason why 用 the reason that 或\介词 + which\取代。
High taxation is often why /that governments fall High taxation is often for which governments fall
the main reason why /that governments fall the main reason for which governments fall
10. 介词+ where/when引导的定语从句
1) from where:\从哪儿\，where代表主句提供的地点名词 主句 He stood near the window, We went up to the roof, The car stopped short only a few inches from where引导的定语从句 from where he could see the tower. from where we had a good view of the procession. from where I stood. 2) since when \从那以后\；by when \在那时候\。when代表主句提供的时间名词或时间背景。 主句
主句 介词+ when引导的定语从句 I bought the car ten years ago, since when I have used no others. She settled in Shanghai, by when she had obtained a master's degree.
11. 嵌入式定语从句
嵌入式定语从句是指关系代词在从句中作主语时，因为语气上的需要，后面嵌入一个主谓结构，通常为:I know, I’m sure, they say, he thinks等，然后再接定语从句的谓语和其他部分。例如：
含嵌入成分的定语从句 Animals These are the points I've got an idea She has an adopted son
that we know live in water must have air too. that I think puzzle you. that I'm sure will interest you. who she says was an orphan. 12. 同位定语从句
同位定语从句是指作同位语的名词或代词后紧跟一个定语从句，对该名词或代词进行修饰或限定。同位定语从句可以分为两类。
1）重复型:为了加强语势或出于修辞的需要，重复主句中要被修饰的词或该词的词法变体，
形成同位语结构，然后接关系代词或关系副词再加定语从句。 主句 It is a world of wonders, It is a way of life, He announced that he would run for a second term 重复型同位定语从句 a world where anything can happen. one that I'm toying to follow. an announcement that was acclaimed by most members of the party. 2）总结型：即先提供一个总结主句意义的词作先行词，然后接定语从句。常用名词或代词作同位语总结主句意义，然后接定语从句。 主句 Yesterday I went skating -- In the old days the woman was kept at the bottom of society She gives several reasons why patients should be told the truth, 总结型同位定语从句 something that I hadn't done for years. a slave who could be bought and sold. especially those who are dying. 13. 双重定语从句
就其先行词与定语从句的关系，双重定语从句可以分为两类：
1）并列型：两个定语从句并列修饰同一个先行词，由并列连词连结。关系代词作主语不能省略。 主句 并列型定语从句 Peter shared a flat with a boy who was a philosophy student and who always sat up half the night studying. The course is intended for students who already have a good command of English, but who wish to increase their competence in the language. 关系代词作宾语，第一个定语从句中的关系代词可以省略，第二个定语从句中的关系代词只能用which，且不可省略。 主语 并列型定语从句 谓语 is again on the market. is probably King Lear. The house he bought in 2001, and which he sold five years later, The best play Shakespeare wrote, but which I haven't read,
2）复合型：两个定语从句不在同一层次上，第一个定语从句按定语从句的构成法构成，关系代词作宾语可以省略。第二个定语从句的先行词由第一个定语从句及其修饰的先行词构成，第二个定语从句中的关系代词不可省略。 主句 定语从句（1） 定语从句（2） who can play the piano, that you haven't got? who is so talent as he? She is the only girl (that) they have recruited Is there anything (that) you want Can you mention anyone (that) we have met 14. 分离式定语从句 有时，定语从句不是紧跟在先行词之后，而是位于其他句子成分或谓语之后， 使定语从句
与先行词分离，形式一个分离式定语从句。此类定语从句可分为以下几种情况： 1）先行词后接一个状语，形成先行词与定语从句分离。 主句 被状语分离 There is no student in our class I left the book on the bus 被分离的定语从句 who does not study hard. which I bought last year in Beijing. 被分离的定语从句 that man's foot hasn't trodden. that plays an important part in the lives of its people. 2) 先行词后接另一个定语，形成先行词与定语从句分离。 主句 被另一个定语分离 There are no places left on the earth The country has a river flowing through the city 3）先行词为主句的主语，且主句谓语较短时，定语从句常置于谓语之后形成与先行词分离。 主句（主语是先行词） 被分离的定语从句 Cases will be introduced to readers where the complaints have resulted in the law. The days will come soon when people have enough to eat and wear. 4）先行词为主句的宾语，后面紧接宾语补足语，形成先行词与定语从句分离。 主句(宾语是先行词) You will find the taxis The film brought the hours 被宾补分离 waiting outside back to me 被分离的定语从句 which you can hire to reach there. when I lived in that small village. 15. 准关系代词as的用法
1）准关系代词as引导限制性定语从句。
当先行词被such, the same, as修饰时，连词as可用作关系代词（因而被称作准关系代词），构成such... as, such as, the same ... as, as?as结构，引导定语从句。准关系代词as在从句中可以作主语、宾语或表语。
① such ... as结构:（such修饰先行词，意为\像这样的人或事\）
as作主语 He does not possess such a mind as is necessary to a scientist.
Don't trust such men as praise you to your face. as作宾语 Such a bike as you have is sold out in this shop. as作表语 I've never seen such a clever man as he is. ② such as结构：（such作先行词，意为\像这样的人或事\）
as作主语 It was a new-type school such as had never existed before.
They produced a crop such as had never before been seen.
as作宾语 She seized a chance such as nobody else ever had.
The instrument is not such as I saw in the exhibition.
③ the same ... as结构
as作主语 They faced the same problem as defeated the ancient Romans. as作宾语 This is the same watch as I lost.
as作表语 My hometown is no longer the same one as it was. ④ as ... as结构
as作主语 As many children as came were given some cakes.所有来的孩子都得到了蛋糕。
He is as diligent a man as ever lived.他是世上最勤奋的人。
as作宾语 He was telling the kids as funny a story as he did last time.
说明：① such... as与such...that的区别：such?as引导定语从句；such ... that引导结果状语从句。
They talked in such simple English as children could understand. 他们用孩子们能听懂的简单的英语交谈。 (定语从句)
They talked in such simple English that children could understand it. 他们用十分简单的英语交谈，连孩子们都能听懂。（状语从句） I will provide you with such things as you may need.
我要给你提供一些你可能用得着的东西。
He shut the window with such a force that the glass broke. 他如此用力地关窗，结果玻璃碎了。 ② the same...as 与 the same...that 的区别：the same ... as 指两物相似，the same...that 描述的是同一物。
This is the same bag as I lost yesterday. 这个包和我昨天丢失的（包）相似。（相似物） This is the same bag that I lost yesterday. 这正是我昨天丢失的那个包。（同一物）
2）准关系代词as引导非限制性定语从句。 ① as 引导非限制性定语从句，只代表主句或主句的一部分所表达的意思（不能指代某个名词或代词），在从句中作主语或宾语，可以放在主句前、主句后或主句的中间。 as从句置于句首:
As is known to all, he is the best student in our class. As we all know, he studies very hard. as从句置于句末:
He opposed the idea, as could be expected.
The number of students is increasing, as is mentioned above. as从句置于句中:
Grammar, as has been said9 is not a set of dead rules. Taiwan is, as you know, an inseparable part of China. 常用的这类句式有：
as is said above综上所述 as is mentioned above正如上面提到的 as is known to all 众所周知 as is often the case 通常如此 as is reported in the newspaper 如报纸所报道的
② 在\主句（否定句）引导肯定句\的结构中，as引导的从句不具有否定意义，含义上可用but取代。
主句为否定句, as引导的肯定句有肯定含义
Insects do not have bones, as people have.
Insects do not have bones, but people have bones. 昆虫没有骨骼，而人是有骨格的。
Whales are not fish, as some people think.
Whales are not fish, but some people think they are. 鲸不属于鱼类，而有些人认为它们是鱼。
3) 在非限制性定语从句中，which和as引导定语从句时的区别
① which引导的从句不能放在主句前，而as引导的从句则既可以放在主句前，也可以放在 主句后。
As(√) is often the case, he is absent. Which (×) is often the case, he is absent.
He saw the girl, as(√) he had hoped. He saw the girl, which(×) he had hoped.
② as和which都可以指代一个句子，但as有\正如\、\就像\之意，主要对主句内容进行评 述，which则无此含义。
He is a foreigner, as I know from his accent. ( as 指代一个句子，意为\正如\
He has to work on Sundays, which he doesn't like. ( which 指代一个句子，无\正如\之意) ③ 当从句谓语动词是be或相当于连系动词的seem等时， 可用as/which作主语，但谓语是行为动词时只能用which。
He married her, as was/seemed natural. He married her, which was/seemed natural. He saw the girl, as(×) delighted him. He saw the girl, which (√) delighted him. 4) as可用作连词，引导状语从句，构成省略形式\过去分词\这一特殊结构，译成汉语时其作用如定语。
as shown =as it is shown
The bridge as shown in the picture is really wonderful. 图中所示的桥真是棒极了。 as given = as they are given
See the answers as divert at the end of this book.请参见本书结尾处给出的答案。 as spoken = as it is spoken
English as spoken in Australia is slightly different from British English. ! 澳大利亚所讲的英语与英国英语略有不同。
as evidenced = as it is evidenced
The volcano is still active, as evidenced by the recent eruption.最近的喷发证明，这座火山仍然活跃。
as witnessed = as it was witnessed (witness [?w?tn?s] v. 1.目击，亲眼看见 2.以?作证)
This year's charity ball was the most successful one ever, as witnessed by the number of tickets sold.今年的慈善舞会是最为成功的一次， 这可以从售出的门票数量上看出来。
请看下列常见的\过去分词\结构：as described, as explained, as originally written, as instructed, as listed, as mentioned, as needed, as required, as taught (pp and pt of teach)
16. 准关系代词but的用法
1) but作关系代词，只用于主句为否定(或具有否定含义)的结构。
2) but本身含有否定意义，相当于who/which/that?not,定语从句通过双重 否定达到强烈肯定的修饰效果。
3) but的这一用法在定语从句中总是作主语，谓语动词的数要与先行词一致， 时态与主句相呼应。
主句+ but引导的定语从句有否定含义
There is no rule but has exceptions
There is no rule that has not exceptions 所有规则都有例外。 There is no one but knows about this affair. 没有人不知道此事。
There is no one who doesn’t know about this affair. 人人都知道此事。 There are few books but have a misprint or two .
There are few books which don’t have a misprint or two.几乎每本书都有一两个印刷错误。 说明：but引导状语从句“but = that not”。