主語從句
1． 定義：用作主語的從句叫做主語從句.
2． 構(gòu)成：關(guān)聯(lián)詞+簡單句
3． 引導(dǎo)主語從句的關(guān)聯(lián)詞有三類：
(1) 從屬連詞that. 如：That they were in truth sisters was clear from the facial resemblance between them.
很明顯,她們確是親姐妹,她們的臉型很相似.
(2) 從屬連詞whether.如：
Whether he’ll come here isn’t clear. 他是否會來這里還不清楚.
(3) 連接代詞who, whom, whose, what, which, whoever, whatever, whichever
連接副詞 where, when, how, why.如：
What she did is not yet known. 她干了什么尚不清楚.
How this happened is not clear to anyone. 這事怎樣發(fā)生的,誰也不清楚.
Whoever comes is welcome. 不論誰來都?xì)g迎.
Wherever you are is my home ---- my only home. 你所在的任何地方就是我的家----我唯一的家.
賓語從句
置于動詞、介詞等詞性后面起賓語作用的從句叫賓語從句.賓語從句的語序必須是陳述語序.謂語動詞、介詞、動詞不定式,v.-ing形式后面都能帶賓語從句.有些形容詞（afraid,sure,glad等）之后也可以帶賓語從句.
在復(fù)合句中作主句的賓語,引導(dǎo)詞有：
連詞：that (that ?？墒÷?,whether, if
代詞：who, whose, what ,which
副詞：when ,where, how, why 等.
（一）that引導(dǎo)的賓語從句（在非正式場合that可以省略）
可跟that從句做賓語的動詞有：
say, think, insist, wish, hope, demand, imagine, wonder, know, suppose, see, believe, agree, admit, deny, expect, explain, order, command, feel, dream, suggest, hear, mean, notice, prefer, request, require, propose, declare, report等.
例句：The boy believes that he will travel through space to other planets.
注意事項：當(dāng)主句謂語動詞是 think, believe, suppose, expect 等詞,而賓語從句的意思是否定時,常把否定轉(zhuǎn)移至主句表示.
例句：I don’t think it is right for him to treat you like that.
在以下情況中that不能省略
當(dāng)句中的動詞后接多于兩個由that引導(dǎo)的賓語從句時,第一個that可省,但后面的that不可省.
例句：He said (that) you were too young to understand the matter and that he was asked not to tell you.
當(dāng)主句的謂語動詞與that賓語從句之間有插入語時,that一般不可省.
例句：Just then I noticed, for the first time, that our master was wearing his fine green coat and his black silk cap.
當(dāng)that從句是雙賓語中的直接賓語時,that不可省.
例句：I can’t tell him that his mother died.
注意事項：許多帶復(fù)合賓語的句子,that引導(dǎo)的賓語從句經(jīng)常移到句子后部,而用it作形式賓語.
例句：I find it necessary that we should do the homework on time.
（二）由whether,if 引導(dǎo)的賓語從句
由whether(if)引導(dǎo)的賓語從句,實際上是一般疑問句演變而來的.意思是“是否”.賓語從句要用陳述句語序.一般說來,在賓語從句中whether與if可以互換使用,但在特殊情況下if與whether是不能互換的.
例句：I wonder whether(if) they will come to our party.
只能用whether,不能用if引導(dǎo)的賓語從句
在帶to的不定式前
例句：We decided whether to walk there.
在介詞的后面
例句：I’m thinking of whether we should go to see the film.
在動詞后面的賓語從句時
例句：We discussed whether we had a sports meeting next week
直接與or not連用時
例句：I can’t say whether or not thet can come on time.
只能用if不能用whether引導(dǎo)的賓語從句
if引導(dǎo)條件狀語從句,意為“如果”
例句：The students will go on a picnic if it is sunny.
if引導(dǎo)否定概念的賓語從句時
例句：He asked if I didn’t come to school yesterday.
引導(dǎo)狀語從句even if（即使）和as if（好象）時
例句：He talks as if he has known all about it.
（三）連接代詞和連接副詞引導(dǎo)的賓語從句
這樣的賓語從句實際上是由特殊疑問句變化而來的,賓語從句要用陳述句語序.用于這種結(jié)構(gòu)的動詞常常是：see, say, tell, ask, answer, know, decide, show, find out, imagine, suggest, doubt, wonder, discover, understand, inform, advise等.
英語中的連接代詞有：who,whom,whose,which,what,在句中擔(dān)任主語、賓語、定語或者表語.
例句：Can you tell me whom you are waiting for?
英語中的連接副詞有：when,where,why,how,在句中擔(dān)任狀語的成分.
例句：None of us knows where these new parts can be bought.
表語從句
1． 定義：用作表語的從句叫做表語從句.
2． 構(gòu)成：關(guān)聯(lián)詞+簡單句
3． 引導(dǎo)表語從句的關(guān)聯(lián)詞的種類：
(1) 從屬連詞that.如：
The trouble is that I have lost his address. 麻煩是我把他的地址丟了.
(2) 從屬連詞whether, as, as if.如：
He looked just as he had looked ten years before. 他看起來還與十年前一樣.
The question is whether they will be able to help us. 問題是他們是否能幫我們.
注：從屬連詞if一般不用來引導(dǎo)表語從句,但as if卻可引導(dǎo)表語從句,如：
All this was over twenty years ago, but it’s as if it was only yesterday.
這都是20多年前的事了,但宛如昨天一樣.
能跟表語從句的謂語動詞一般為系動詞be, seem, look等.如：
It looked as if it was going to rain. 看起來天要下雨了.
(3)連接代詞who, whom, whose, what, which, whoever, whatever, whichever
連接副詞 where, when, how, why.
如：The problem is who we can get to replace her. 問題是我們能找到誰去替換她呢.
The question is how he did it. 問題是他是如何做此事的.
That was what she did this morning on reaching the attic. 那就是她今晨上了閣樓干的.
狀語從句
狀語從句(adverbial clause)在句中作狀語,可修飾主句中的動詞、形容詞和副詞等.狀語從句由從屬連詞引導(dǎo).狀語從句可放在句首或句末.放在句首時,從句后面常用逗號；放在句末時,從句前面往往不用逗號.
When the plane arrived, some of the detectives were waiting inside the main building while others were waiting on the airfield.
當(dāng)飛機抵達(dá)時,一部分偵探等在主樓里面,而另一部分則等在停機坪上.
When I came home, my wife was cooking dinner. 我回家時,妻子在做晚飯.
Though he was poor, he was happy. 雖然他很窮卻很快樂.
If you ask him, he will help you. 如果你向他請求,他會幫助你.
Since you ask, I will tell you. 你既然問,我就告訴你.
I can't tell you when you won't listen. 既然你不想聽,我就不告訴你了.
He stopped trying, when he might have succeeded next time. 他不再試了,其實他可能下一次就成功.
定語從句
定語從句是由關(guān)系代詞和關(guān)系副詞引導(dǎo)的從句,其作用是作定語修飾主句的某個成分,定語從句分為限定性和非限定性從句兩種.
一、 限定性定語從句
1. that即可代表事物也可代表人,which代表事物；它們在從句中作主語或賓語,that在從句中作賓語時?？墒÷躁P(guān)系詞,which在從句中作賓語則不能省略.而且,如果which在從句中作“不及物動詞＋介詞”的介詞的賓語,注意介詞不要丟掉,而且介詞總是放在關(guān)系代詞which的前邊,但有的則放在它原來的位置
2. which作賓語時,根據(jù)先行詞與定語從句之間的語義關(guān)系,先行詞與which之間的介詞不能丟
3. 代表物時多用which,但在帶有下列詞的句子中用that而不用which,這些詞包括all, anything, much等,這時的that常被省略
4. who和whom引導(dǎo)的從句用來修飾人,分別作從句中的主語和賓語,whom作賓語時,要注意它可以作動詞的賓語也可以作介詞的賓語
5. where是關(guān)系副詞,用來表示地點的定語從句
6. when引導(dǎo)定語從句表示時間
〔注〕值得一提的是,表示時間“time"一詞的定語從句只用when引導(dǎo),有時不用任何關(guān)系代詞,當(dāng)然也不用that引導(dǎo)
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 besiness trip, he brings a lot of living necessities, such as towers, soap, toothbrush etc.
7. whose是關(guān)系代詞,修飾名詞作定語,相當(dāng)于所修飾成分的前置所有格
8. 當(dāng)從句的邏輯主語是some, any, no, somebody, anybody, nobody, something, anything, everything或nothing時,常用there is來引導(dǎo)
二、非限定性定語從句：非限定性定語從句的作用是對所修飾的成分作進一步說明,通常和主句間用逗號隔開,將從句拿掉后其他部分仍可成立
1. which引導(dǎo)的非限定性定語從句來說明前面整個句子的情況或主句的某一部分
2. 在引導(dǎo)限定性定語從句時,that有時相當(dāng)于in which, at which, for which或at which
Attitudes towards daydreaming are changing in much the same way that(in which) attitudes towards night dreaming have changed. 人們對白日做夢的態(tài)度正在改變,這與人們對夜間做夢的看法的變化有非常相似之處.
I like the music for the very reason that(for which) he dislike it. 我出于某種原因喜歡這種音樂,而他恰恰與我相反.
We arrived the day that(on which) they left. 剛好我們到的那天他們走了.
3. 有時as也可用作關(guān)系代詞
4. 在非限定性定語從句中,不能用that,而用who, whom代表人,用which代表事物