Unit 3 数词

概述

一、定义：表示数目、数字和数目顺序的词称为数词。

二、分类：①基数词：表示数字或数目的多少。②序数词：表示数目的顺序。

专题一 基数词的构成和句法功能

一、基数词的构成

1．基数词1～12。

这12个数字的英语表达是独立的词。

eg. 1→one 2→two 3→three 4→four 5→five 6→six 7→seven 8→eight 9→nine 10→ten 11→eleven 12→twelve

2．基数词13～19。

多在词尾加teen，但13，15，18有变动。

eg.13→thirteen 14→fourteen 15→fifteen 16→sixteen 17→seventeen 18→eighteen 19→nineteen

3．基数20～99。

（1）20～90整十的基数词多以ty结尾。注意20，30，40，50和80的拼法。

eg.20→twenty 30→thirty 40→forty 50→fifty 60→sixty 70→seventy 80→eighty 90→ninety

（2）表示“几十几”时，十位与个位之间要用连字符连接。

eg.21→twenty-one 45→forty-five 86→eighty-six 99→ninety-nine

4．基数词100～999。

100→a/one hundred，101～999都在hundred后加and，再加1～99的基数词。

eg.101→a/one hundred and one 333→three hundred and thirty-three

845→eight hundred and forty-five 999→nine hundred and ninety-nine

5．千以上的基数词。

从数字的右端向左端数起，每三位加一个逗号。从右端开始，第一个逗号前的数字后添加thousand；第二个逗号前的数字后添加million；第三个逗号前的数字后添加billion；第四个逗号前的数字后加trillion。两个逗号之间的最大的数为百位数形式。

eg.2, 784→two thousand, seven hundred and eighty-four

18, 250, 088→eighteen million, two hundred and fifty thousand and eighty-eight

88, 123, 850, 748, 045→eighty-eight trillion, one hundred and twenty-three billion, eight hundred and fifty million, seven hundred and forty-eight thousand and forty-five

二、基数词的句法功能

基数词可在句中作主语（S）、宾语（O）、表语（P）、定语（Att）和同位语（App）等。

eg. Five are absent.五个人缺席了。（S）

—How many fish did you catch？你抓了多少条鱼？

—I caught twenty.我抓了二十条。（O）

Five multiplied by five is twenty-five.5×5=25.(P)

There are fifty computers in the classroom.教室里有50台计算机。（Att）

Is there room for us three？有我们3个人的位子吗？（App）

基础训练（一）

一、下列是英语中的四则运算符号：①+：plus/and；

②-：minus/from；③×：times/multiplied by；

④÷：over/divided by；⑤=：equal（s）/is equal to，或is/are，或makes/make。

用英语写出下列算式。

1．5+4=9

__________

2．8-8=0

__________

3．15+25=40

__________

4．28-7=21

__________

5．2×8=16

__________

6．8÷2=4

__________

7．5+7=?

__________

8．25-5=?

__________

二、表示“几点过几分”用“分钟+past+小时”（分钟不超过半小时）；表示“几点半”用“half/thirty past+小时”；表示“差几分到几点钟”，用“分钟+to+小时”（分钟超过半小时）。

根据上述结构用英语写出下列时间。

1．8:15__________

2．8:45__________

3．9:05__________

4．7:40__________

5．12:20__________

6．11:50__________

7．7:58__________

8．2个半小时__________

9．1:30__________

专题二 序数词的构成和句法功能

一、序数词的构成

1．1～10表示为：first（1st），second（2nd），third（3rd），fourth（4th），fifth（5th），sixth（6th），seventh（7th），eighth（8th），ninth（9th），tenth（10th）。

2．11～19表示为：eleventh（11th），twelfth（12th），thirteenth（13th），fourteenth（14th），fifteenth（15th），sixteenth（16th），seventeenth（17th），eighteenth（18th），nineteenth（19th）。

3．20～90的整十的序数词：twentieth（20th），thirtieth（30th），fortieth（40th），fiftieth（50th），sixtieth（60th），seventieth（70th），eightieth（80th），ninetieth（90th）。

4．21～99的序数词：表示几十的基数词+连字符+序数词。

eg. Twenty-first第二十一thirty-second第三十二forty-third第四十三fifty-fifth第五十五sixty-eighth第六十八ninety-ninth第九十九。

5．第一百以上多位序数词的构成：将最后一个基数词变为序数词。

eg. a hundredth第一百a thousandth第一千a millionth第一百万a billionth第十亿one hundred and twenty-first第一百二十一

请记基数词变为序数词口诀：

二、序数词的句法功能

序数词在句中作主语（S），宾语（O），表语（P），定语（Att）和状语（Ad）。

eg. The third is what he really needs.第三个是他真正需要的。（S）

I prefer the eighty-eighth.我更喜欢第八十八个。（O）

Jane is always the first to come to school.简总是第一个到学校。（P）

Jim was the first boy to get the present.吉姆是得到此礼物的第一个男生。（Att）

When we first lived here，there were no subways.我们最初住在这儿时，没有地铁。（Ad）

注意：作状语时，序数词前不用加the。

基础训练（二）

一、写出下列序数词的完整形式

1．1st__________

2．2nd__________

3．3rd__________

4．4th__________

5．5th__________

6．8th__________

7．9th__________

8．10th__________

9．12th__________

10．13th__________

11．15th__________

12．18th__________

13．21st__________

14．22nd__________

15．23rd__________

16．45th__________

17．78th__________

18．99th__________

二、用英语写出下列短语

1．第518号房间

2．第129路公交车

3．第1001夜

4．第35课

5．第九部分

6．1949年10月1日

7．1988年3月28日

8．第25页

9．第45中学

专题三 分数、小数、百分数和概数

一、分数的构成和句法功能

1．分数的构成。

（1）分数由基数词和序数词合成。分子是基数词，分母是序数词。

（2）分子等于1时，分母用单数；分子大于1时，分母用复数。

eg.→ one/a half→one-third→one-fourth/a quarter→six-sevenths→three quarters/three-fourths

请记分数的构成口诀：

（3）分子和分母的数目都较大时，两者都用基数词，之间用over/by/out of连接。

eg.→forty-five over/by/out of one hundred and forty-seven

→forty-seven over/by/out of ninety-nine

2．分数的句法功能。

分数（与被修饰的名词一起）在句中作主语（S）、宾语（O）、表语（P）、定语（Att）、同位语（App）和状语（Ad）。

eg. Seven-tenths of the population are farmers.十分之七的人口是农民。（S）

I spent three-fifths of my salary（工资）paying for the dress last month.上个月我花了五分之三的工资来买这条裙子。（O）

Kathy's earning（收入）is four-fifths of her husband's.凯西的收入是丈夫的五分之四。（P）

He ate one-third apple.他吃了三分之一的苹果。（Att）

Thirty students，one-fifth of this grade，were chosen into the football team.占全年级学生总数五分之一的三十名学生被选进了足球队。（App）

Houses cost one-third more this year than they did five years ago.今年房价比五年前上涨了三分之一。（Ad）

二、小数的读法

小数点读作point，零读作zero，小数点前按基数的读法读数，小数点后每位数字应单独读出。

eg.0.12→zero point one two 14.163→ fourteen point one six three

三、百分数的读法

百分数中的数字按基数的读法读，“%”读作percent。

eg.20%→twenty percent.

四、概述的表达

1．表示“大于”或“多于”。

（1）over/above+数字，more than+数字。

（2）数字+and more/or more/and above。

eg. forty years or more四十多年

2．表示“小于”或“少于”。

（1）less than+数字，under/below+数字，almost/nearly+数字。

（2）数字+or less

eg. a mile or less最多一英里

基础训练（三）

一、用英语写出下列数字

1．

2．

3．

4．

5．

6．

7．20%

8．99%

9．0.02

10．14.44

二、将下面短语译成英语

1．30美元的裙子__________

2．2个月的假期__________

3．200千米的公路__________

4．100米宽的河__________

5．200千克的猪__________

6．3000多名学生__________

7．90%的人口__________

8．75%的学生__________

9．不足2美元__________

10．零摄氏度以下__________

11．36 ℃__________

12．-4 ℃__________

13．10米长__________

14．2千克重__________

专题四 数词的其他用法

一、数词的运用

1．表示编号：序数词位于名词之前且加定冠词；基数词用在名词后。

eg. No. 888 Room= Room 888/Room No. 888第888号房间

No. 105 Bus= Bus 105/Bus No. 105 105路公交车

the twenty-second page=Page 22第22页

2．“数词+连字符+名词”或“数词+连字符+名词+形容词”构成复合形容词。

eg. a two-week holiday两周的假期a 100-mile-long journey一段100英里长的旅程

3．表示“几十几岁”，用“in one's+‘20至90整数的复数’”。

He went to England in his sixties.他在六十多岁时去了英格兰。

4．表示年代：in+the+年代。

eg. in the 1960s/1960s'在20世纪60年代，读作：in the sixties of the 20th century。

5．“a+序数词”表示“再一个，又一个”。

eg. After eating two apples，he ate a third one.吃了两块蛋糕后，他又吃了一块。

6．“每隔……”的表达方式。

eg. every other day每隔一天every three days每隔两天

every third day每逢第三天every four years每四年

二、倍数的表示法

1．A is+倍数+形容词/副词比较级+than B，表示“A的大小/数量/长度/速度……是B的多少倍”或“A比B大/多/长/快……（‘多少’减一）倍”。

eg. This river is three times longer than that one.这条河是那条河的三倍长。/这条河比那条河长两倍。

2．A is+倍数+as+形容词/副词原级+as B，表示“A是B的多少倍”。

eg. This novel is three times as thick as that one.这本小说的厚度是那本小说的三倍。

3．A is+倍数+the+名词（size，height，weight，length，width...）+of B，表示“A的大小/高度/质量/长度/宽度……是B的多少倍”。

eg. This building is four times the size of that one.这幢楼是那幢楼的四倍大。

4．A is+倍数+as many/much+名词+as B，表示“A是B的多少倍”。

eg. We've produced five times as many cars this year as we did five years ago.今年我们生产的小汽车是五年前的五倍。

三、hundred，thousand，million，billion，trillion的用法

此类数词前有数词表示确定的数目时，其后不加s；表示模糊的数量时，其后要加上s，且常加of短语，也可在前面加some，several，many，tens of...等修饰。

eg. two hundred 200 many thousands of成千上万的

基础训练（四）

一、将下列短语翻译成英语

1．第八单元

2．一个十六岁的女孩

3．在她五十多岁时

4．在19世纪90年代

5．又第四次收网

6．又有了第五个孩子

7．2019年11月21日

8．数以十亿计种生物

二、单项选择

1．Ten years ago the population of our village was__________that of theirs.

A. as twice large as

B. twice as large as

C. twice as much as

D. as twice much as

2．The elephant is__________the horse.

A. the five times weight of

B. three times the weight of

C. as three times heavy as

D. three times as heavier as

3．The factory produced__________toys in 2017 as the year before.

A. as twice many

B. as many as

C. as twice as many

D. twice as many

能力训练

一、用适当的数词填空，完成下列句子

1．One__________years is a century.

2．There are__________seasons, __________months, about__________weeks, __________days and__________hours in a year.

3．Chairman Mao Zedong was born on__________（1893年12月26日）.

4．Christmas Day is on December the__________.

5．Letter“K”is the__________letter in the alphabet（字母表）.

6．The Chinese Communist Party was founded on__________（1921年7月1日）.

7．—How much is seven-eighths minus one half?

—It's__________.

8．—How much is 2 multiplied by 444, 444, 444?

—It's__________.

二、用所给词的适当形式填空

1．Who was the__________ (twelve) to arrive at school this morning?

2．Yu Xinya prefers reading the__________ (eight)lesson to reading the__________ (forty-five) one.

3．The photo of the hero is on Page__________ (thirty-first).

4．Nowadays in China__________ (million) of people have their own cars.

5．Liu Xiaoqing, a famous film star, looks young and beautiful. It's hard to believe that she's in her__________ (sixty).

6．—What's the time now?

—It's__________ (10:25).

三、单项选择

1．（2016·乌鲁木齐）__________Kobe's fans watched his final match and__________of them were men.

A. Million of; three fourths

B. Three millions; third four

C. Millions of; three fourths

D. Three million; third fours

2．（2016·宜宾）There are__________months in a year. December is the__________month of a year.

A. twelve; twelve

B. twelfth; twelfth

C. twelve; twelfth

D. twelfth; twelve

3．（2017·恩施）—Enshi is becoming a popular tourist destination（目的地）now.

—I think so.__________people come here every summer vacation.

A. hundreds and thousands of

B. Hundred and thousand

C. Hundreds and thousands

4．（2017·资阳）Cindy likes stamps very much. She has collected about two__________stamps from different countries so far.

A. thousand of

B. thousand

C. thousands of

D. thousands

5．（2017·哈尔滨）—How do you keep fit？

—I live on__________floor. I walk upstairs instead of taking the lift every day.

A. twelve

B. the twelve

C. the twelfth

6．—Do you have enough students to clean the laboratory?

—No, I think we need__________students.

A. two another

B. two others

C. more two

D. two more

实战训练

一、从括号内选择正确的单词或短语填空

1．Rose received a letter full of love from her parents on her__________ (sixteen's, sixteenth) birthday.

2．—What does the fresh juice contain（包含）？

—__________ (Fourth-fives; Four-fifths) of the juice is orange. It's very pure.

3．William Shakespeare was born in__________ (the 1660, the 1660's).

4．It is reported that the United States uses__________ (twice much as, twice as much) energy as the whole Europe.

5．__________ (Several million, Several millions)people in the world are sending information by WeChat every day.

6．The village is far away from here. It's__________ (a four-hour, four hours') walk.

二、改错：下列每道题目都有一处错误，指出并改正

三、单项选择

1．（2016·天水）__________of the farmland here__________with rice.

A. Two thirds; is covering

B. Two third; is covered

C. Second third; are covering

D. Two thirds; is covered

2．（2016·随州）—If your parents wanted to have a__________child，would you agree？

—Of course. But they should make it in__________years'time.

A. second; second

B. two; two

C. second; two

D. two; second

3．（2016·东营）—A recent survey shows that 35 out of 45 students in my class will save their phones first in a fire.

—About__________of the students made such a choice? Life is far more important, isn't it?

A. half

B. one third

C. two thirds

D. three quarters

4．（2017·咸宁）—Who won the first prize of the__________World Table Tennis Championship？

—You mean the match held in__________? Ma Long did.

A. fifty-four; German

B. fifty-fourth; Germany

C. fifty-fourth; German

D. fifty-four; Germany