英語語法知識(shí)難點(diǎn)3

1、英語語法知識(shí)難點(diǎn)（三）編 稿：李俊和 審 稿：畢 勤 責(zé) 編: 隋 瑜（十）情態(tài)動(dòng)詞與助動(dòng)詞 i 要點(diǎn)助動(dòng)詞本身無意義，在句中幫助主要?jiǎng)釉~構(gòu)成一定的時(shí)態(tài)，語態(tài)、語氣，或是幫助構(gòu)成否定句和疑問句，常用的助動(dòng)詞有be, do, have, shall(should), will(would).情態(tài)動(dòng)詞表一定的詞義，本身并不表示動(dòng)作或狀態(tài)，而僅僅表達(dá)說話人的態(tài)度，它在句中須和主要?jiǎng)釉~一起構(gòu)成謂語，主要的情態(tài)動(dòng)詞有can(could), may (might), must, have to, ought to, need, dare, shall, should, will, would.1、can

2、能，可以，表說話人同意，許可還可表客觀條件許可，如:you can go now.提建議或請(qǐng)求時(shí)可用can i, can you表客氣，如can i buy you a drink?can和be able to表能力時(shí)的區(qū)別。can表一般具有的能力，be able to表在特定條件下的能力，如:although the driver was badly hurt, he was able to explain what had happened.2、may（1）、可以，表說話人同意，許可或請(qǐng)求對(duì)方許可。you may go.（2）、（現(xiàn)在和將來）可能，也許，只用于肯定句和否定句中，如he ma

3、y not be right.3、must, have tomust表主觀上的必須，have to表客觀上的必須，如:its getting late. i have to go. -must i go now. -yes, you must.(no, you neednt./ no, you dont have to.)4、need, dare這二詞有實(shí)意動(dòng)詞和情態(tài)動(dòng)詞兩種詞性，如用作實(shí)意動(dòng)詞后接動(dòng)詞不定式to do，如用作情態(tài)動(dòng)詞后接動(dòng)詞原形。need i go now? -yes, you must./no, you neednt.)5、shall用于第一人稱疑問句中表說話人征求對(duì)方的意

4、見或向?qū)Ψ秸?qǐng)求，如，shall we begin our lesson?用于二、三人稱陳述句，表說話人命令、警告、允諾、威脅等口吻，如: you shall fail if you dont work harder.6、should表應(yīng)該，意為有責(zé)任，有義務(wù)。如:we should try our best to make our country more beautiful.7、will表有做某事的意志、意愿、安心、打算，如 will you lend me your book? yes, i will.，8、should have done表應(yīng)該做而未做must have done表對(duì)過去

5、事實(shí)的肯定推測(cè)could have done表本可以做某事9、判斷句：肯定句用must, 否定句用cant, 不太肯定用may, mighthe must be in the office now.he must have gone to bed, for the light is out.he cant be in the office. he is at home.he couldnt have cleaned the classroom, because he didnt come here today.he might be in the office, i am not sure.h

6、e might have cleaned the room, i suppose.ii 例題例1，they _ to walk in the street at night.a. didnt dare b. not dared c. not dare d. dared not解析，該題答案為a， 此空需選一動(dòng)詞作謂語，因?yàn)楹竺媸莟o walk, didnt dare是行為動(dòng)詞dare過去時(shí)態(tài)的否定形式。例2，when he was very old, mr. smith _ sit for hours without saying a word.a. would b. should c. mu

7、st d. used解析，該題答案為a, would此處表過去的傾向性，習(xí)慣性動(dòng)作，意為總是如: when we were children, we would go swimming every summer.（十一）句子種類i 要點(diǎn)句子按使用目的可分為陳述句、疑問句、祈使句和感嘆句；按結(jié)構(gòu)又分為簡(jiǎn)單句、并列句和復(fù)合句。1、陳述句的否定（1） 在含有賓語從句的主從復(fù)合句中，當(dāng)主句的謂語動(dòng)詞是think, expect, believe, suppose, guess, fancy, imagine等，且主句主語是第一人稱時(shí)，賓語從句謂語的否定習(xí)慣上要移到主句謂語上，如: i dont thi

8、nk he is right.（2） 含有否定意義的副詞never, seldom, hardly, scarcely, rarely, barely的句子應(yīng)視為否定句，如: i have never been there before.2、反意疑問句（1） need和dare 既可作情態(tài)動(dòng)詞，又可作實(shí)意動(dòng)詞，在反問部分須加以區(qū)別，如we neednt leave, need we? we dont need to leave, do we?（2） 陳述部分出現(xiàn)否定意義的副詞或代詞如never, seldom, few, hardly, little等時(shí)，反問部分須用肯定形式如：he seld

9、om comes, does he?（3） 陳述部分用不定代詞作主語時(shí)，反問部分的主語用it ，如：nothing can stop me, can it?陳述部分用everybody, everyone, somebody, someone，等作主語時(shí)，反問部分常用it，有時(shí)也用they，如:everybody knows that, dont they?（4） 陳述部分包括used to 時(shí)，反問部分可有兩種形式，如: you used to get up early, usednt (didnt) you?（5） 陳述部分是there + be結(jié)構(gòu)時(shí)，反問部分用there，如:there

10、s something wrong with you, isnt there?（6） 陳述部分是含有賓語從句的主從復(fù)合句時(shí)，反問部分的主語和謂語應(yīng)和主句保持一致，如: he never told others what he thought, did he?但，如果是i think , i believe等 +賓語從句時(shí)，反問部分須和從句的動(dòng)詞保持一致，如，i dont think he is right, is he? i dont believe he does that, does he?3、感嘆句用what或how, what a beautiful park it is.how be

11、autiful a park it is.how beautiful the park is.how we worked!4、祈使句take care!dont stand there.please open the door for the old lady.ii例題例1，dont forget to post the letter, _ ?a. will you b. do you c. wont you d. shall you解析：該題答案為a， 在否定句、祈使句后只用will you?，但肯定的祈使句后可用如，wait for me, will (wont, can, cant, c

12、ould) you?例2，lets go out for a walk, _ ?a. will you b. wont you c. shall we d. do we 解析：該題答案為c，lets后加上shall we來表語氣婉轉(zhuǎn)、客氣，而在let us后加上will you。例3，he hardly writes to you, _ ?a. doesnt he b. does he c. do they d. has he解析：該題答案為b，hardly否定副詞，反問部分要用肯定形式。（十二）各種從句i要點(diǎn)根據(jù)從句在句中的句法功能，從句可分為名詞性從句、定語從句和狀語從句。1、 名詞性從句

13、（1） 主語從句what he wants is a piece of paper.it is believed that he can solve the problem.注：主語從句的謂語動(dòng)詞用單數(shù)。（2）賓語從句i dont know how to solve the problem.do you know where he lives?（3）表語從句the problem is who can help me.this is why i came here.（4）同位語從句i have no idea where he went.i heard the news that he wou

14、ld come.同位語從句用that引導(dǎo)，常跟在fact, idea, news, promise, thought, message, hope, belief, doubt等詞后，that在從句中不作任何成分。2、定語從句在復(fù)合句中，修飾某一名詞或代詞，或修飾整個(gè)主句的從句叫做定語從句，引導(dǎo)定語從句的關(guān)系代詞有who, whom, whose, which, that, as,和關(guān)系副詞when, where, why。（1）that指物時(shí)一般可與which互換，但在下列情況下，要用that而不用which。a. 先行詞有all, everything等不定代詞時(shí)，如，everything

15、 (that) he did is wrong.b. 先行詞被all, every, no, some, any, little, much等修飾時(shí)，如，ill read all the books (that) you lend me.c. 先行詞被序數(shù)詞或形容詞最高級(jí)修飾時(shí)，this is the first letter (that) the boy has written.d. 先行詞被the only, the very, the same, the last修飾時(shí)，如he is the very man (that) im looking for.e. 只用which的情況在介詞后

16、或在非限定性定語從句中this is the book about which we have talked a lot.the book, which he gave me yesterday, is very interesting.f. where和when作關(guān)系副詞this is the room where i worked.this is the room which i stayed in.i remembered the day when we lived there.i remembered the day that i spent there.g. as和which as

17、可以放于句首，而which 不可以as you know, he is good at english.three of them 和three of whichi have a lot of books, three of which are in russian.i have a lot of books and three of them are in russian.3、狀語從句在復(fù)合句中起狀語作用的從句叫做狀語從句。狀語從句可分為時(shí)間狀語、地點(diǎn)狀語、原因狀語、目的狀語、結(jié)果狀語、條件狀語、行為方式狀語、比較狀語、讓步狀語等多種。ii 例題例1、 _ i accept the gift

18、 or refuse it is none of your business.a. if b. whether c. even if d. no matter when解析：該題答案為b。whether可以和or連用，if不可以，此外if一般僅用于賓語從句。例2、the way _ these comrades look at problems is wrong.a. where b. in that c.x d. with which解析：該題答案為c，先行詞是way，定語從句中用that或 in which來引導(dǎo)或不填。例3， _a long time since i saw you la

19、st time.ait was b. it is c. it had been d. it can be 解析：該題答案為b，it is +時(shí)間數(shù)+ since引導(dǎo)的從句是一個(gè)句型，意為從時(shí)候以來過了多久了。（十三）主謂一致i 要點(diǎn)謂語受主語支配，須和主語在人稱和數(shù)上保持一致，這叫做主謂一致，主謂一致包括語法一致、意義上一致和就近一致。1、語法上一致（1）、以單數(shù)名詞或代詞，動(dòng)詞不定式短語、動(dòng)名詞短語或從句作主語時(shí)，謂語動(dòng)詞要用單數(shù)，主語為復(fù)數(shù)時(shí)，謂語用復(fù)數(shù)，如，to work hard is necessary for a student.（2）、用and或bothand連接的并列主語，謂語

20、動(dòng)詞用復(fù)數(shù)，如，both he and i are right.但并列主語如果指的是同一人，同一事物或同一概念，謂語動(dòng)詞用單數(shù)，如, his teacher and friend is a beautiful girl.（3）、主語是單數(shù)時(shí)，盡管后面跟有as well as, but ,except, besides, with ,along with, together with, like等，謂語動(dòng)詞仍用單數(shù)，如，the teacher as well as his students is excited.（4）、某些不定代詞，如做主語，謂語動(dòng)詞要用單數(shù)，如:everyone has a book.（5）、一些只有復(fù)數(shù)形式的名詞，如people, cattle, clothes等作主語時(shí)，謂語動(dòng)詞要用復(fù)數(shù)，如，a lot of people are dancing outside.2、意義上一致（1）、表時(shí)間、距離、價(jià)格、度量衡等的名詞作主語時(shí)，謂語動(dòng)詞通常用單數(shù)，如，twenty years is not a long time.（2）、表示總稱意義的名詞public, police, cattle, clothes等作主語時(shí)，謂語動(dòng)詞用復(fù)數(shù)，如，