主從復(fù)合句

　　1、概念：

　　主從復(fù)合句由一個(gè)主句和一個(gè)或一個(gè)以上的從句構(gòu)成。主句為句子的主體,從句只用作句子的一個(gè)次要成分,不能獨(dú)立成為一個(gè)句子。從句通常由關(guān)聯(lián)詞引導(dǎo),并由關(guān)聯(lián)詞將從句和主句聯(lián)系在一起。如：While the grandparents love the children, they are strict with them.(爺爺奶奶們很愛孩子,同時(shí)對(duì)他們也嚴(yán)格要求。) / It seemed as if the meeting would never end.(看起來會(huì)議沒完沒了。) / Hurry up, or (else) you'll be late.(快點(diǎn), 要不然就來不及了。) / However I cook eggs, the child still refuses to eat them.(不管我用什么方法煮雞蛋,小孩還是不肯吃。)

　　2、分類：

　　從句按其在復(fù)合句中的作用,分為主語從句、表語從句、賓語從句、定語從句和狀語從句等。(參見以下各條)

　　3、各從句在句子中的位置以及用法：

　　(1) 表語從句：在句子中作連系動(dòng)詞的表語的從句,它位于主句中的系動(dòng)詞之后。

　　例如：That is why he did not come to school yesterday. / It is because you are so clever.

　　(2) 賓語從句：在句子中作及物動(dòng)詞或介詞的賓語。

　�、倩�本形式：(主句+)連詞+從句主語+從句謂語+...

　�、� 關(guān)于賓語從句連詞的選擇：

　　若從句來源于一個(gè)陳述句,那么,連詞用that,在口語中that可以省略;

　　若從句來源于一個(gè)一般疑問句,連詞則用if 或whether;

　　若從句來源于一個(gè)特殊疑問句,則連詞就是疑問詞(如what,who,where,when等)

　　例如：They believe that the computer will finally take the place of human beings.(他們相信計(jì)算機(jī)終將代替人類。) (從句本來就是陳述句)/ I wonder whether I should say something for him to the headmaster. (我不知道是不是該為他在校長跟前說點(diǎn)什么。) (從句來源于一般問句Shall I say something for him to the headmaster?) / He asked me where he could get such medicine. (他問我在哪兒能搞到那樣的藥。) (從句來源于特殊問句Where can he get such medicine? )

　�、� 賓語從句的時(shí)態(tài)問題：如果主句是現(xiàn)在時(shí),從句則用現(xiàn)在某一時(shí)態(tài),甚至可以用過去時(shí);

　　如主句是過去時(shí),從句則相應(yīng)地使用過去某一時(shí)態(tài),遇到客觀真理時(shí)仍然用現(xiàn)在時(shí)。如：I think I will do better in English this term. (我想本學(xué)期我的英語會(huì)學(xué)得好點(diǎn)。) / The teacher asked the boy if the earth is round. (老師問那個(gè)男孩地球是不是圓的。)

　�、� 下列結(jié)構(gòu)后面的從句一般也作為賓語從句看待：

　　be sorry / afraid / sure / glad +that從句,如：I’m sorry I’m late. (對(duì)不起,我遲到了。) / I’m afraid he isn’t in at the moment. (恐怕他此刻不在家。)

　　(3) 狀語從句：在復(fù)合句中作狀語,其位置可以在主句前或主句后。狀語從句可以分為時(shí)間、地點(diǎn)、原因、目的、結(jié)果、比較、讓步、條件等幾種。狀語從句由從屬連接詞引導(dǎo)。

　　時(shí)間狀語從句通常由when ,as ,while, after, before, since, as soon as ,since, till (until), while, whenever 等引導(dǎo)。時(shí)間狀語從句一般放在句首或句尾,特別注意,時(shí)間狀語從句不允許使用將來時(shí),而應(yīng)該用現(xiàn)在時(shí)替代。如： When you finish the work, you may go out to play with Sam. (你完成工作就可以出去和Jim一起玩了。) / I won’t leave until Mum comes back. (媽媽回來了我才會(huì)走。)

　　地點(diǎn)狀語從句通常由 where, wherever等引導(dǎo)。如：Go back where you came from! (哪里來還滾到哪里去!) / I will never forget to catch the thief who stole my necklace wherever he may be. (我永遠(yuǎn)也不會(huì)忘記去抓住那個(gè)偷我項(xiàng)鏈的賊,無論他會(huì)在哪里。)

　　原因狀語從句通常由because, since, as等引導(dǎo),一般放在句首或句尾。如：He went abroad because his father had found a good university for him. (他出國了,因?yàn)樗�父親給他找了一所好大學(xué)。)

　　目的狀語從句通常由so that..., so...hat..., in order that... 等引導(dǎo),往往放在句尾,從句中通常含有can / could / may / might等情態(tài)動(dòng)詞。如：He got up earlier so that he could catch the first train. (他起身更早為的是趕上第一班車。)

　　結(jié)果狀語從句通常由 so that..., so...that... 等引導(dǎo),放在句尾。結(jié)果狀語從句一般表示已經(jīng)發(fā)生的事情,故多為過去時(shí)態(tài)。如：He lost so many bikes that he decided never to buy a new one. (他丟了那么多輛自行車,他決定再也不買新車了。)比較狀語從句通常由as, than, as (so)...as等引導(dǎo),一般省略從句的謂語部分,只剩下名詞或代詞(用主格或賓格均可)。如：Jane is much taller than I/me. (Jane比我高多了。) / I don’t have as many books as you (do). (我書沒有你多)

　　讓步狀語從句通常由though (although), as, even if( even though), however, whatever等引導(dǎo)。如：Even if you pay the debt(債務(wù)) for me, I will not thank you because it has nothing to do with me. (即使你替我還了債我也不會(huì)感謝你,因?yàn)樗�與我毫無關(guān)系。) / He wears a T-shirt though it is very cold. (他穿了一件T恤衫,盡管天很冷。)

　　條件狀語從句通常由if, unless, as long as等引導(dǎo),條件狀語從句一般放在句首或句尾,特別注意,時(shí)間狀語從句不允許使用將來時(shí),而應(yīng)該用現(xiàn)在時(shí)替代。You will certainly fail in the coming final exams unless you work much harder. (即將來到的期末考試你肯定考不及格,除非你更用功。) / If it doesn’ t rain tomorrow, we shall go hiking. (如果明天不下雨我們就要去徒步旅行。)

　　[注意] 1、because與so;(al)though與but;if與so不可以同在一個(gè)句子中成對(duì)出現(xiàn)。

　　2、時(shí)間、條件、原因,讓步狀語從句放在句首時(shí)需要用逗號(hào)與主句隔開。

　　(4) 定語從句：在復(fù)合句中作定語用修飾句子中某一名詞或代詞的從句叫定語從句。

　�、� 定語從句的位置：放在名詞或代詞的后面。如：The man who has an umbrella in his hand is my uncle. (手上抓了一把雨傘的人是我的叔叔。)

　　② 語法術(shù)語的改變：被修飾的名詞或代詞稱為先行詞;引導(dǎo)定語從句的連接詞稱為關(guān)系詞,其中that、which、who稱為關(guān)系代詞,where、when、how稱為關(guān)系副詞。

　�、� 關(guān)系代詞或關(guān)系副詞的作用：

　　關(guān)系代詞who、whom 和whose指人,分別在從句中作主語、賓語和定語。which指物that多指物, 有時(shí)也指人,它們在從句中可以作主語或賓語。定語從句中關(guān)系代詞作從句賓語時(shí)可以省略。This is the thief (that/who/whom) we have been looking for these days. (這個(gè)就是我們近日一直在找的小偷。) / Please find a room which is big enough for all of us to live in. (請找一間足夠大能住下我們?nèi)�體的房間。)

　　關(guān)系副詞when或where引導(dǎo)定語從句時(shí),它們在從句中分別作時(shí)間狀語和地點(diǎn)狀語。如：This is the room where they had a quarrel a week ago. (這是一個(gè)星期前他們吵架的房間。) / I can never forget the day when I first saw you. (我永遠(yuǎn)不會(huì)忘記第一次見到你的日子。)

　　④ 限制性定語從句和非限制性定語從句。限制性定語從句在句中不能省略,否則主句意思就不完整。非限制性定語從句和主句之間往往用逗號(hào)分開,這種從句是一種附加說明,如果從句子中省去,也不致于影響主句的意思。如：She spent the whole evening talking about her latest book, which none of us had heard of. (她一個(gè)晚上都在談?wù)撍�最近的�?我們一個(gè)人都沒有聽說過那本書。)

　　[注解]

　　1、關(guān)系代詞只能用that的情況：當(dāng)先行詞是指事物的不定代詞(all, anything等),或先行詞部分含有最高級(jí),或含有序數(shù)詞時(shí),不能用其他的關(guān)系代詞,只能用that. 如：All that Lily told me seems untrue. (Lily告訴我的話似乎不真實(shí)。) / Can you give me anything that has no sugar inside? (能不能給我點(diǎn)里面沒有糖的東西?) / This is the first two-story bus that runs in our city. (這是第一輛運(yùn)行于我市的雙層公交車。)

　　2、關(guān)系代詞在從句中作主語時(shí)一般用who(指人)、that(指物),而不用that指人或用which指物。 如：Do you know the woman who is weeping in the corner? (你認(rèn)識(shí)那個(gè)在角落里哭泣的女人嗎?) / Do not tell me any words that have nothing to do with me. (跟我無關(guān)的話,請一個(gè)字也不要說。)

　　3、關(guān)系代詞作從句的賓語時(shí),常用which或whom,較少使用that或who,而且,關(guān)系代詞常常省略。如：Tom’s father was the first parent whom our teacher talked to. (Tom的父親是我們老師第一個(gè)談話的人。)

　　4、當(dāng)關(guān)系代詞緊跟在介詞后面時(shí),必須用which或whom,而當(dāng)介詞移到句尾時(shí),則又可以使用that或who. 如：This is the room in which Miss Li once lived. (= This is the room Miss Li once lived in.) (這是李小姐曾經(jīng)居住過的房間。)

　　(5) 主語從句：在句子中充當(dāng)句子主語的從句叫主語從句。位于謂語動(dòng)詞之前。通常由that,whether以及疑問連詞引導(dǎo)。一般情況下,常用it替代主語從句,而將主語從句移到句尾。如：When we should start is still a question. (我們該在什么時(shí)候開始還是個(gè)問題呢。)