壹个芝麻糕
如何学好语法知识是值得每个学生深刻思考和体会的。接下来是我为大家整理的 九年级英语 语法知识点整理归纳，希望大家喜欢!
九年级英语语法知识点整理归纳一
一、过去完成时与现在完成时的区别
现在完成时表示的动作发生在过去，以现在的时间为基点，但侧重对现在产生的结果或造成的影响，与现在有关，其结构为“助动词 have (has) + 过去分词”;过去完成时则是一个相对的时态，已过去时间为基点，它所表示的动作不仅发生在过去，更强调“过去的过去”，只有和过去某时或某动作相比较时，才用到它。
比较：I have learned 1000 English words so far.到目前为止我已经学会了 1000 个 英语单词 。
I had learned 1000 English words till then.到那时为止我已经学会了 1000 个英语单词。
— I'm sorry to keep you waiting. 对不起，让你久等了。
— Oh, not at all. I have been here only a few minutes.没什么，我只等了几分钟。(“等”的动作从过去某一时间点持续到现在)
二、过去完成时与一般过去时的区别
虽然这两种时态都表示过去发生的动作或存在的状态，但在使用时应注意以下几点：
1. 时间状语不同：过去完成时在时间上强调“过去的过去”;而一般过去时只强调过去某一特定的时间。
比较：They had arrived at the station by ten yesterday.
They arrived at the station at ten yesterday.
2. 在没有明确的过去时间状语作标志时，谓语动词动作发生的时间先后须依据上下文来判断：先发生的用过去完成时，后发生的则用一般过去时。
She was very happy. Her whole family were pleased with her, too.She had just won the first in the composition competition.
3. 当两个或两个以上接连发生的动作用 and 或 but 连接时，按时间顺序，只需用一般过去时来代替过去完成时;另外，在 before ， after ， as soon as 引导的从句中，由于这些连词本身已经表示出时间的先后，因此也可以用过去时来代替过去完成时。
He entered the room, turned on the light and read an eveningpaper.
Ⅰ. MultipleChoices.
1.I lost the dictionary I ________.
A.have bought B.bought C.had bought D.had been bought
2.The train had gone when my brother _______ at the station.
A.have arrived B.arrived C.had arrived D.am arriving
3. Mary _______ of visiting her grandmother, but the bad weathermade her change her mind.
A.has thought B.thought C.had thought D.had been thought
4.------Did you meet Tom at the airport? ------No，he _______ by the time I______ there.
A.has left;got B.had left;arrived C.left;arrived D.left;had got
5.-------Why didn’t Tom attend the meeting yesterday? -------He __________ Beijing.
A.has gone to B.had gone to C.went to D.had been to
6.-------I _______ to come to help you. ------But you didn’t come.
A.have meant B.had meant C.meant D.will mean
7.Finally one of my friends _______ by Beijing University，for which she ___ five timA.were admitted; had tried B.was admitted; had tried C.were admitted; has tried D.was admitted; tried
8.------I have bought you the books you want. ------Oh，good，I _______ afraid you had forgotten.
A.was B.am C.had been D.have been
9.We _________ four thousand new words by the end of last year.
A.had learned B.have learned C.learned D.will have learned
10.Helen _______her keys in theoffice so she had to wait until her husband ______home.
A.has left;comes B.left;had come C.had left;came D.had left;would come
11. My father _________ to the hospital when I hurried home.
A. had gone B. went C. had been taken D. had been sent
12. ----- Jim, ________ you _________ your homework?
----- Yes, of course, but I ________ it late bed time.
A. do do; finished B. did do; had finished C. have done; hadfinished D. have done; finished
13. You ____ football after school. Why not go home and do yourhomework first?
A. always played B. are always playing C. have always played D.have always been playing
es
14. Eversince Picasso’s painting went on exhibit, there ____ large crowds at the museumevery day.
A. is B. has been C. have been D. had been
15. ---What do you think of my suggestion? --- Sorry. What’s that?I _____ about something else.
A. was thinking B. thought C. am thinking D. had thought
Ⅱ. Fill in theblanks according to the meanings of the sentences by using tenses of the verbs.
1. How many English songs ___________ she __________ (learn) bythe end of last month?、
2. Hardly _______ I ______ (get) on the bus when it started tomove
3. He __________________(read) the book before he was ten yearsold.
4. She said she ___________________ (see) the film before.
5. Our English teacher _________________ (teach) English inGuangxi for ten years before he came to No.113 Middle School.
6. By the end of last month, they _________________(complete)thebridge .
7. No sooner ________ I _______ (go) out than he came to see me.
89. The classroom _______________ (clean) before we ___________(get) there yesterday.
10. ________ the boy ___________ (finish) his homework before yousaw him?
11. When we got to the station, the train _____________ already_____________. (leave)
12. The book __________ by the end of last month. (finish)
13. When I got back to the shop , my bag _________________ (take)away by someone else.
14. When I arrived at the cinema, the film _________________ (be)on for ten minutes.
15. ---What’s that terrible noise?
---The neighbors ______ (prepare) for a party.
16. The mayor of Beijingsays that all construction work for the Beijing Olympics ______ ( complete) by2006.
17. The teacher, with 6 girls and 8 boys of her class, ______(visit) a museum when the earthquake struck.
18. ---Mr. Johnson didn’t turn up at the meeting yesterdaymorning, did he?
--- No. We __________ (wait) till twelve o’clock. A whole morningwas wasted.
19. ---Why haven’t you asked her to come here?
---She _______ (do) an important experiment when I found her andshe ________ (not, finish) it.
答案：
Keys:
Ⅰ. 1-5 CBCBB 6-10BBAAC 11-15. DDBCA
Ⅱ. 1. had learnt2. had got 3. had read 4. had seen 5. had taught 6. had completed 7. had gone8. had gone 9. had been cleaned, got 10. Had finished 11. had left 12. had beenfinished 13. had been taken 14. had been on 15. are preparing 16. will havebeen completed 17. was visiting 18. were waiting 19. was doing, hasn’t finished
九年级英语语法知识点整理归纳二
语法：直接引语变间接引语。
直接引用别人的话叫直接引语，用来转述别人的话叫间接引语。例：
Hesaid,"HewillgotoBeijingtomorrow."(直接引语)
HesaidthathewouldgotoBeijingthenextday.
直接引语变间接引语时时态、人称及一些时间或个别词都要做相应的改变。
①时态：
一般现在时→一般过去时一般将来时→过去将来时
现在进行时→过去进行时一般过去时→过去完成时
现在完成时→过去完成时
_真理性的 句子 时态不变。例：
Hesaid:"Thesunrisesintheeast."
Hesaidthatthesunrisesintheeast.
他说太阳从东方升起。
②时间：
now→then,lastmonth→themonthbefore.
today→thatday,threedaysago→threedaysbefore.
tonight→thatnight,tomorrow→thenextday.
yesterday→thedaybefore,thedayaftertomorrow→intwodays.
③ 其它 变化：
this→thatthese→thosehere→there
come→go
句式的改变：
①直接引语是陈述句加"that"可以省去。例：
Hesaid,"Mysisterwasherethreedaysago."→
Hesaidthathissisterhadbeentherethreedaysbefore.
②直接引语是一般疑问句，变成用if/whether引导的宾语从句，人称时态等作相应改变。
Motheraskedme,"Didyoubuyanymeatforlunch?"→
Motheraskedmeif/whetherIhadboughtsomemeatforlunch.
③直接引语是特殊问句，变成由原来疑问词一样的连接词引导的宾语从句，时态人称等作相应改变。例：
"Whatdoyoudo?"heaskedme.
HeaskedmewhatIdid.
④直接引语是选择问句变成由whether或if引导的宾语从句。
"DoyoulikeEnglishorChinese?"Heaskedme.
HeaskedmewhetherIlikedEnglishorChinese.
语法：被动语态
1.英语中动词有两种语态：主动语态和被动语态
主动语态表示主语是谓语动词动作的执行者，被动语态表示主语是谓语动词动作的承受者。
当我们强调谁是某个动作的执行者，即"谁做了某种事情"时，用主动语态。
eg:Danielboughtanewcomputer丹尼尔买了一台新电脑。(不是别人)
如果主语不是动作的执行者，而是动作的承受者时，就是被动语态。
eg:AnewcomputerwasboughtbyDaniel一台新电脑被丹尼尔买了。
被动语态的谓语由be+动词的过去分词构成，其中be是助动词，随时态改变。
一般现在时的被动语态由"am/is/are+动词的过去分词"构成。
一般过去时的被动语态由"was/were+动词的过去分词"构成。
2.被动语态的用法：
当不知道或没必要说明动作的执行者时，用被动语态。
eg:RiceisgrowninSouthChina.华南 种植 水稻。(没必要说明是谁种)
Thisbridgewasbuilt100yearsago.这座桥是100年前建的。(不知道谁建的)
Passivevoicewith'by'
在被动语态中，如果我们也要把动作的执行者表达出来的话，我们就在被动句子的后面，用"by+动作的执行者(宾格)"来表示。
e.g.Jackbrokethewindow.(主动语态)
ThewindowwasbrokenbyJack.(被动语态)窗户是被杰克打碎的。
Mealsarecookedbyhermotherathome.在家饭是她母亲烧的。
Thebookwaswrittenbyhimseveralyearsago.这本书是他几年前写的。
3.难点：
1).当一个含有复合宾语(宾语+宾补)的句子变为被动语态时，只能把宾语变为被动语态的主语，宾补还放在原来的位置。
e.g.WecallhimXiaoWang.---HeiscalledXiaoWang.
Hecuthishairshort.---Hishairwascutshort.
2).带双宾语的动词变为被动语态时，常常把间接宾语变为被动语态的主语;如果直接宾语变为被动语态的主语时，间接宾语前要加介词to或for.
e.g.Someonegavetheboyanapple.--Theboywasgivenanapple.
Anapplewasgiventotheboy.
Hismotherboughtapresentforhim.---Hewasboughtapresent.
Apresentwasboughtforhim.
3).在let,hear,watch,see,help,have等词的句子中，主动语态不加to,被动语态要加to.
e.g.Thebossmakesuswork12hoursaday.---Wearemadetowork12hoursaday.
Theyheardthechildrensingthatmorning.---Thechildrenwereheardtosingthatmorning.
⑤直接引语是祈使句，根据说话语气变成ask/tell/orderwarnsb.todosth.的结构。例：
Shesaidtome,"Standup."→
Sheaskedmetostandup.
Fathersaidtohisson,"Don'tplayfootballinthestreet."→
Fathertoldhissonnottoplayfootballinthestreet.
语法：祈使句
表示命令、叮嘱等的句子叫祈使句。祈使句省略主语，以动词原形开头，常加please表示客气。常有以下三种结构：
(1)行为动词开头。例：
Sitdown,please.(Pleasesitdown.)
Comehere.
Gothere.
(2)系词be开头。
Becareful!
Besilent.
(3)Let开头。例：
Let'sdoitatonce.
Lethimdoit.
注：(1)祈使句的否定式在句首加don't。例：
Don'tspeakinChinese.别用汉语说。
Don'tbeheresoearly.别来这太早。
(2)在祈使句前可以加never或always。
Neverclimbuptoohigh.It'sdangerous.
Alwayscomeontime.总是准时。
Alwaysbepolitetoothers.总是对人礼貌。
语法：并列句
由并列连词but，and，or，so，while等构成的并列句，例：
HehelpsmeandIhelphim。
Hewasill，buthestillworkedon。
Helikescookingwhilehiswifelikestravelling。
语法：条件状语从句，以if引导。
if在英语中可以构成条件状语从句，意为“如果”，也可以构成宾语从句，意为“是否”。例：
Idon‘tknowifhewillcometomorrow。(宾从)
我不知道他明天是否来。
Ifhecomes，I’llletyouknow。(条从)
如果他来，我让你知道。
_1)在if构成的条件状语从句中，如果主句是将来时，或祈使句或有情态动词，从句通常用一般现在时。如上面的例句，再如：
Hecanpasstheexamifhestudieshard。
如果他努力学习会通过考试的。
(2)if构成的条件从句可以放于句子前面，也可以放于后面。例：
Ifitrains，Iwon‘tgowithyou。
如果下雨我就不和你去了。
Iwon’tgowithyouifitrains。
九年级英语语法知识点整理归纳三
【篇一】一般过去时：
1.概念：过去某个时间里发生的动作或状态;过去习惯性、经常性的动作、行为。
2.时间状语：ago,yesterday,thedaybeforeyesterday,lastweek,last(year,night,month...),in1989,justnow,attheageof5,oneday,longlongago,onceuponatime,etc.
3.基本结构：be动词;行为动词的过去式
4.否定形式：was/were+not;在行为动词前加didn't，同时还原行为动词。
5.一般疑问句：was或were放于句首;用助动词do的过去式did提问，同时还原行为动词。
6.例句：Sheoftencametohelpusinthosedays.
Ididn'tknowyouweresobusy.
【篇二】现在进行时
：
1.概念：表示现阶段或说话时正在进行的动作及行为。
2.时间状语：now,atthistime,thesedays,etc.
3.基本结构：am/is/are+doing
4.否定形式：am/is/are+not+doing.
5.一般疑问句：把be动词放于句首。
6.例句：Howareyoufeelingtoday?
Heisdoingwellinhislessons.
【篇三】过去进行时：
1.概念：表示过去某段时间或某一时刻正在发生或进行的行为或动作。
2.时间状语：atthistimeyesterday,atthattime或以when引导的谓语动词是一般过去时的时间状语等。
3.基本结构：was/were+doing
4.否定形式：was/were+not+doing.
5.一般疑问句：把was或were放于句首。
6.例句：AtthattimeshewasworkinginaPLAunit.
Whenhecamein,Iwasreadinganewspaper.
【篇四】现在完成时：
1.概念：过去发生或已经完成的动作对现在造成的影响或结果，或从过去已经开始，持续到现在的动作或状态。
2.时间状语：recently,lately,since...for...,inthepastfewyears,etc.
3.基本结构：have/has+done
4.否定形式：have/has+not+done.
5.一般疑问句：have或has。
6.例句：I'vewrittenanarticle.
Thecountrysidehaschangedalotinthepastfewyears.
【篇五】过去完成时：
1.概念：以过去某个时间为标准，在此以前发生的动作或行为，或在过去某动作之前完成的行为，即"过去的过去"。
2.时间状语：before,bytheendoflastyear(term,month...),etc.
3.基本结构：had+done.
4.否定形式：had+not+done.
5.一般疑问句：had放于句首。
6.例句：Assoonaswegottothestation,thetrainhadleft.
Bytheendoflastmonth.Wehadreviewedfourbooks
【篇六】一般将来时：
1.概念：表示将要发生的动作或存在的状态及打算、计划或准备做某事。
2.时间状语：tomorrow,nextday(week,month,year...),soon,inafewminutes,by...,thedayaftertomorrow,etc.
3.基本结构：am/is/are/goingto+do;will/shall+do.
4.否定形式：was/were+not;在行为动词前加didn't，同时还原行为动词。
5.一般疑问句：be放于句首;will/shall提到句首。
6.例句：Theyaregoingtohaveacompetitionwithusinstudies.
Itisgoingtorain.
【篇七】过去将来时：
1.概念：立足于过去某一时刻，从过去看将来，常用于宾语从句中。
2.时间状语：thenextday(morning,year...),thefollowingmonth(week...),etc.
3.基本结构：was/were/goingto+do;would/should+do.
4.否定形式：was/were/not+goingto+do;would/should+not+do.
5.一般疑问句：was或were放于句首;would/should提到句首。
6.例句：HesaidhewouldgotoBeijingthenextday.
Iaskedwhowasgoingthere.
【篇八】将来完成时：
1.概念：在将来某一时刻之前开始的动作或状态
2.时间状语：bythetimeof;bytheendof+时间 短语 (将来);bythetime+从句(将来)
3.基本结构：begoingto/will/shall+havedone
玖兰卅麻
为了中考英语，九年级的同学们，对于英语语法也复习过了吧。下面是我带来九年级初三英语语法希望对大家有帮助。
名词的分类：根据用法，名词可以分为可数名词和不可数名词两类。
1.可数名词有单、复数形式的区别。需要掌握规则名词的复数形式的构成。
*以y结尾的专有名词，或元音字母+y 结尾的名词变复数时，直接加s变复数：
如：two Marysthe Henrys monkey---monkeysholiday---holidays
比较： 层楼：storey ---storeys story---stories
* 以o 结尾的名词，变复数时：
a. 加s，如： photo---photospiano---pianos radio---radioszoo---zoos;
b. 加es，如：potato--potatoes tomato--tomatoes
*以f或 fe 结尾的名词变复数时常去 f , fe 加 ves ，
如：half---halvesknife---knivesleaf---leaveswife---wiveslife---lives thief---thieves
2.名词复数的不规则变化
1)child---children foot---feet tooth---teeth mouse---miceman---men
woman---women
注意：与 man 和 woman构成的合成词，其复数形式也是 -men 和-women。
如： an Englishman，two Englishmen. 但German不是合成词，故复数形式为Germans;Bowman是姓，其复数是the Bowmans。
2)单复数同形如：deer，sheep，fish，Chinese，Japanese li，jin，yuan，two li，three mu，four jin但除人民币元、角、分外，美元、英镑、法郎等都有复数形式。如:a dollar, two dollars; a meter, two meters
3)以s结尾，仍为单数的名词，如：
a. maths ，politics，physics等学科名词，为不可数名词，是单数。
b. news 是不可数名词。
c. the United States，the United Nations 应视为单数。
The United Nations was organized in 1945. 联合国是1945年组建起来的。
d. 以复数形式出现的书名，剧名，报纸，杂志名，也可视为单数。
"The Arabian Nights" is a very interesting story-book.
<<一千零一夜>>是一本非常有趣的 故事 书。
4) 表示由两部分构成的东西，如：glasses (眼镜)trousers,clothes若表达具体数目，要借助数量词 pair(对，双);suit(套); a pair of glasses; two pairs of trousers
5) 另外还有一些名词，即可做不可数名词也可做可数名词，但意思不相同。
词语可数名词不可数名词词语可数名词不可数名词
fire火炉，火灾火Paper报纸，试卷纸
Exercise练习， 体操 锻炼，运动Time次数时间
Fish鱼(种类，条数)鱼肉Light灯光线
Chicken鸡，小鸡鸡肉Orange橘子橘子汁
room房间空间glass玻璃杯玻璃
单词可数名词意思不可数名词意思单词可数名词意思不可数名词意思#FormatBD_0#
work作品，著作工作German德国人德语
wood森林木头life生命生活，人生
Chicken小鸡鸡肉Exercise练习，体操运动，锻炼
Paper报纸，试卷纸Orange橘子橙汁
Room房间空间Glass玻璃杯玻璃
Time次数，倍数时间Japanese日本人日语
Light灯光线fish鱼(种类)鱼肉
6.)常以复数形式出现并使用的名词：clothes, people, trousers, glasses, scissors, thanks, congratulations, wishes, police, stairs(楼梯), works(著作), woods(森林), times(时代)
3.不可数名词量的表示 可以借助单位词表一定的数量。如：
a glass of water 一杯水 a piece of cake
4.修饰可数名词的词有：many, few, a few, a number of, 数词
修饰不可数名词的词有：much, little, a little, a great deal of
即可修饰可数名词也可修饰不可数名词的词有：some (any), no, a lot of
二、定语名词的复数 (即名词修饰名词)
名词作定语一般用单数，但也有以下例外。
1) 用复数作定语。 如：sports meeting 运动会 students reading-room 学生阅览室
2) man, woman, 等作定语时，其单复数以所修饰的名词的单复数而定。
如：men workerswomen teachers
3) 数词+名词作定语时，这个名词一般保留单数形式。
如：two-dozen eggs两打/(二十四个鸡蛋) a ten-mile walk 十里路 two-hundred trees 两百棵树 a five-year plan.一个五年计划 some banana trees two book stores
三、名词的格
1.有生命的人、物及其他名词的所有格在词尾加“’s”，如the boy’s bag 男孩的书包
2. 若名词词尾已有-s ，只加’，如：Teachers’ Day the twins’ parents, the students’ books
3. 时间、距离、地域等名词的所有格形式为-’s today’s newspaper, ten minutes’ walk the city’s problem
4. 在表示店铺或教堂的名字或某人的家时，名词所有格的后面常常不出现它所修饰的名词，如：the barber's 理发店 at my aunt’s (house) go to the doctor’s .
5. 凡不能加"'s"的名词，都可以用"名词+of +名词"的结构来表示所有关系，如：the title of the song 歌的名字 the window of the house 。
6. 如果两个名词并列，并且分别有's，则表示"分别有";只有一个's，则表示'共有'。
如：John's and Mary's rooms(两间) John and Mary's room(一间)
7. 双重所有格形式：a novel of Mark Twin’s a friend of my father’s / mine
1.人称代词
1.)人称代词的主格在 句子 中作主语，例如：
John waited a while but eventually he went home.
约翰等了一会儿，最后他回家了。
说明：在复合句中，如果主句和从句主语相同，代词主语要用在从句中，名词主语用在主句中， 例如：When he arrived, John went straight to the bank.
2.)人称代词的宾格在句子中作动词的宾语或介词宾语，第一人称在省略句中，还可以作主语。 例如：I saw her with them。 her做宾语，them做介词宾语，
a. -- Who broke the vase?--谁打碎了花瓶?
b. -- Me.--我。(me = It's me.)在正式文体中这里应为I。
宾格代替主格：
a.在简短对话中，当人称代词单独使用或在not 后，多用宾语。
---- I like English.--我喜欢英语。 ---- Me too.--我也喜欢。
---- Have more wine?--再来点酒喝吗? ---Not me.--我可不要了。
b.在表示比较的非正式的文体中，常用宾格代替主格。 但如果比较状语的谓语保留，则主语只能用主格。He is taller than I/me. He is taller than I am.
3)动物名词的指代一般用it或they代替，有时也用he, she，带有亲切的感情色彩。
Give the cat some food. She is hungry.给这猫一些吃的。她饿了。
4)指代车或国家，船舶的名词，含感情色彩时常用she。
1)单数人称代词并列作主语时，其顺序为： you, he / she and I
You, he and I should return on time.
2) 复数人称代词作主语时，其顺序为： we, you and they
*注意：在承认错误，承担责任时，第一人称放在前面
It was I and John that made her angry. 是我和约翰惹她生气了。
*it的主要用法:可以表示天气, 时间, 距离, 形式主语, 形式宾语, 身份等.
2. 物主代词(…人的): 包括形容词性的物主代词和名词性的物主代词
形容词性的物主代词 + 名词; 名词性的物主代词= 形容词性的物主代词+ 名词
3.反身代词：(1)加强语气，起强调作用，“…自己”, “亲自”, “本人”
(2)用在一些动词后,表示主语既是动作的发出者,也是动作的承受者.常见的这类动词有:teach, dress, help, look after, enjoy, hurt, wash
4.不定代词
(1) none (of)指人或物 回答how many / much的问题
nobody, no one 指人 nothing指物
(2) one指人或物, 复数为ones, that指物(不可数名词),it指代前面提到的物体
I have got a nice watch. Would you like to buy one? ( a watch)
I have got a nice watch. Do you like it? ( the watch)
The weather here is better than that in Beijing. (the weather)
(3) 三者或三者以上： all (全部，都) any (任何一个) none (一个也没有)
两者： both (全部，都) either (任意一个) neither(一个也没有)
(3)
全部, 都任意一个全都不,一个也没有
两者botheitherneither
三者或以上allonlynone
*Neither of us is from the USA.
None of us have / has ever been there before.
*not与both, all 连用表示部分否定.
(4)some用于肯定句中,也可用于表示请求、建议或希望得到肯定答复的疑问句中
any用于疑问句、否定句中;还有“任何的”意思
(5)another泛指 另一个
the other常与 one 连用，表示两者中的另一个 one…the other…
others 泛指别的，其他的 the others特指别的，其他的(有范围限制)
(the) others = (the) other + 名词
else放在合成不定代词或疑问词之后
(6)every + 名词， 只能做定语， (三者或三者以上)
each两者或两者以上的“每一”， 可以单独使用
常见的 短语 ：each of each other
(7)合成不定代词的用法(略)*形容词后置
(8)many, few, a few + 可数名词复数
much, little, a little+不可数名词
*little 作形容词， 小的
a little 还可以修饰形容词和副词的比较级和最高级
表示数目多少或顺序多少的词叫数词，数词分为基数词和序数词。表示数目多少的数词叫基数词;表示顺序的数词叫序数词。
一、基数词
1.基数词写法和读法： 345three hundred and forty-five;
2.基数词一般是单数形式，但下列情况，常用复数：
1.) 与of 短语连用，表示概数，不能与具体数目连用，如hundreds of;
2.)表示"几十岁";in his forties
3.)表示"年代"，用 in +the +数词复数;in the 1980s / 1980’s
二、序数词
1.)序数词的不规则变化及缩写形式： first---1stsecond---2ndthird—3rd fifth—5th ninth twelfth twentieth twenty-first----21st
2.)序数词前通常使用定冠词the，但有时使用不定冠词a, an,表示“又一，再一”Try it again, please.请再试一次。 When I sat down a third man came in.
三、 数词的用法
1.倍数表示法
1.) 主语+谓语+倍数(或分数)+ as + adj. + as
I have three times as many as you.我有你三倍那么多。
2.) 主语+谓语+倍数(分数)+ the size (amount，length…) of…
The earth is 49 times the size of the moon.地球是月球的49倍。
3.) 主语+谓语+倍数(分数)+ 形容词(副词)比较级+ than…
The grain output is 8 percent higher this year than that of last year.
今年比去年粮食产量增加8%。
4.) 还可以用by+倍数，表示增加多少倍
The production of grain has been increased by four times this year.
今年粮食产量增加了4倍。
2.分数表示法：基数词代表分子，序数词代表分母。分子大于1时，分子的序数词用单数，分 母序数词用复数：1/3 ---one-third ; 2/3 ---two thirds.
1/4 ---one fourth a quarter
