原因狀語從句知識(shí)講解

1、精品文檔二、原因狀語從句：1、 定義：在句中用來說明主句原因的句子叫原因狀語從句。2、 常用引導(dǎo)詞 ：because個(gè)為）,as （由于）,si nee （既然）,now （that）（既然）3、 時(shí)態(tài)：原因狀語從句一般都是根據(jù)實(shí)際情況選用適當(dāng)?shù)臅r(shí)態(tài)。通常是主過從過，主現(xiàn)從現(xiàn)。4、because, since 和 as 的區(qū)別：1）because引 I導(dǎo)的原因狀語從句一般放于主句的后面，because從句位于句首時(shí)要用逗號(hào)分開，放在句末時(shí)，可不用逗號(hào)分開。because表示直接原因， 語氣最強(qiáng)， 最適合回答why引導(dǎo)的疑問句。because of也表示原因，但它后面不接從句 ，只能接名詞，代詞

2、或動(dòng) 名詞。注意：because和so不可同時(shí)出現(xiàn)在一個(gè)句子里。 I do it because I like it. = I like it so I do it. We went by bus because it was cheaper. = It was cheaper so we went by bus. He cartgo to school because of his illness.2）si nee引導(dǎo)的原因狀語從句一般放于主句之前表示已知的、顯然的理由（通常被翻譯成 既然"=now that ）, 較為正式，語氣比because弱。 Since you are f

3、ree today, you had better help me with my mathematics. Since you don't trust him, you should not employ him. Now （that） you are grown up, you should not rely on your parents.3）as引導(dǎo)原因狀語從句時(shí)表示附帶說明的雙方已知的原因”含有對(duì)比說明的意味，語氣比since弱，較為正式，位置較為靈活（常放于主句之前）。 As it is raining, you ' d better take a taxi. As

4、 you are tired, you had better rest. I went to bed early, as I was exhausted.4）for引導(dǎo)的是并列句表示原因但并不說明主句行為發(fā)生的直接原因，只提供一些輔助性的補(bǔ)充說明，for引導(dǎo)的并列句只能放于主句之后并且必須用逗號(hào)將其與主句隔開。 He could not have seen me, for I was not there. He seldom goes out now, for he is very old.三、目的狀語從句：1、定義： 在句中用來作目的狀語的句子叫目的狀語從句。2、 常用引導(dǎo)詞 ：so tha

5、t（以便）,in order that （以便）3、 時(shí)態(tài)：目的狀語從句一般都是根據(jù)實(shí)際情況選用適當(dāng)?shù)臅r(shí)態(tài)。也通常是主過 _ 從過，主現(xiàn)從現(xiàn)。4、目的狀語從句應(yīng)注意以下：1）目的狀語從句中常含有 ca n, could, may, might, should, will, woul等情態(tài) 動(dòng)詞。I got up early so that I could catch the first bus.2）在口語中so可以引導(dǎo)目的狀語從句。We'll sit nearer the front so we can hear better.3）in order that與 in order to

6、的區(qū)別： in order that +從句 =so that +從句 in order to+動(dòng)詞原形 =so as to +動(dòng)詞原形（不放于句首）=to+動(dòng)詞原形I get up early in order to catch the early bus.=I get up early in order that I can catch the early bus.四、結(jié)果狀語從句：1、定義： 在句中用來作結(jié)果狀語的句子叫結(jié)果狀語從句。2、 常用引導(dǎo)詞： sothat （如此以致 ），suchthat （如此以致）3、 時(shí)態(tài)：結(jié)果狀語從句一般都是根據(jù)實(shí)際情況選用適當(dāng)?shù)臅r(shí)態(tài)。也通常是主過 從

7、過，主現(xiàn)從現(xiàn)。4、結(jié)果狀語從句的句型：結(jié)果狀語從句的從句部分是補(bǔ)充說明主句中謂語動(dòng)詞發(fā)生的結(jié)果的，通常位于主句之后。結(jié)果從句中通常不用情態(tài)助動(dòng)詞，但must, can, could除外。結(jié)果狀語從句其規(guī)律由so與such的不同詞性決定。such是形容詞，修飾名詞或名詞詞組，so是副詞，只能修飾形容詞或副詞。so還可與表示數(shù)量的形容詞many, few, much, little連用，形成固定搭配。7.精品文檔精品文檔1) so +形/畐H+ that從句 The boy isso young that he can't go to school. He speaks so fast t

8、hat no one can catch him2) so + many/few( + 復(fù)名)+ that從句There are so many picture-story books that the boy won't leave.3) so + much/ little (+ 不可數(shù)名詞)+that從句time.He gave me so little time that it was impossible for me to finish the work4) so+ 形 + a/an+ 單名 + that從句It was so hot a day that they wan

9、ted to go swim ming.5) such+ a/an+形 + 單名 + that從句=so+ 形 + a/an+單名 + that 從句He is such a young boy that he can't go to school.=He is so young a boy that he can't go to school.6) such+形+復(fù)名/不可數(shù)名詞+ that從句 They are such fine teachers that we all hold them in great respect. It is such nice weather

10、 that I would like to go to the beach.5、結(jié)果狀語從句與簡單句的轉(zhuǎn)換：1) sothat 從句為肯定句)=形/副 + enough + (for sb.) to do sth.He is so old that he can go to school alone. =He is old enough to go to school alone.2) sothat 從句為否定句)=too形 /副 + (for sb.) to do sth.The problem is so hard that I 'anork it out.=The problem

11、 is too hard for me to work out.=The problem ireasy eno ugh for me to work out.五、讓步狀語從句1、 定義：在句中用來表示 退一步說 ”的句子叫讓步狀語從句。2、常用引導(dǎo)詞 ：although （雖然）=though （盡管，即使）,no matter+疑問詞= 疑問詞-ever （無論 ），even if = even though （即使），whether. or （不管是 還是 等。3、 時(shí)態(tài)：讓步狀語從句的時(shí)態(tài)一般采用主過從過，主將從現(xiàn)的原則。_4、讓步狀語從句的注意點(diǎn)：1） although/ though

12、不可與but連用（二者只選其一），但可與still / yet連用。 Although / Though he is very old, still he is quite strong. Although he was ill , he went to school. = He was ill but he went to school.2) no matter +疑問詞=疑問詞-ever 無論”引導(dǎo)讓步狀語從句可互換) Whatever (= No matter what) happe ned, he would not mind. Whoever (= No matter who) yo

13、u are, you must keep the law. However (=No matter how) expenS iveay be, I ' II take it.注意："no matter+疑問詞”結(jié)構(gòu)只能引導(dǎo)讓步狀語從句，而疑問詞-ever”還可以引導(dǎo)名詞性從句(主語從句，賓語從句，表語從句和同位語從句)。 ril eat whatever no matter what) you give (mteatever引導(dǎo)賓語從句) Whoever專 no matterhw) comes will be welcom(whoever 引導(dǎo)主語從句 )六、條件狀語從句1、

14、 定義：由引導(dǎo)詞if或unless引導(dǎo)的狀語從句叫做條件狀語從句。2、常用引導(dǎo)詞:if如果),unless = if-not (如果不/除非),so/as long as只要)3、 時(shí)態(tài)：條件狀語從句的時(shí)態(tài)常采用主將從現(xiàn)原則。 I will come to see you if I have time. Let's go out for a walk unl ess you are too tired.=Let's go out for a walk if you _are not too tired. You can't lear n En glish well unl ess you work hard.dou You may borrow my book as long as you keep it clea n.注意:“祈使句，+ and / or +簡單句”是一個(gè)固定句型，這里祈使句相 當(dāng)于一個(gè)由if引導(dǎo)的條件狀語從句：用and引導(dǎo)的簡單句常表示一個(gè)較好的結(jié)果，用or引導(dǎo)的簡單句常表示一個(gè)不愉快或不理想的結(jié)果；謂語動(dòng)詞常用一般將來時(shí)。即： 祈使句，and +簡單句（一般將來時(shí)）=If you do sth, you ' ll do sth.'ll find a way.（這個(gè)句型表示 如果做到了祈使句表示的事情，