数 词
英语数词表示数目或者顺序， 可分为基数词和序数词。基数词表示数量，序数词表示顺序。
知识梳理：提纲挈领，抓住重点和难点！
一、基数词的构成
1．1-12的基数词是独立的单词，即： one，two，three，four，five，six，seven，eight， nine，ten，eleven，twelve。
2．13-19的基数词以-teen结尾。如： fourteen，seventeen等，但13，15，18较特殊， 13-thirteen 15-fifteen 18-eighteen。
3．20-90的整十位均以-ty结尾。如： sixty，ninety，但20，30，40，50，80较特殊， 20-twenty 30-thirty 40-forty 50-fifty 80-eighty。
4．十位数与个位数之间要加连字符号"-"，如：28-twenty-eight，96-ninety-six。
5．百位和十位（若无十位则和个位）之间加and，如：148-one hundred and forty-eight 406-four hundred and six。
6．hundred（百），thousand（千），million（百万），billion（十亿）等前面即使有具体的数词，也不能在它们的后面加s。如：600-six hundred，8百万-eight million。
7．1000以上的数字，从后往前数每三位加一个逗号"，"第一个逗号前为千（thousand），第二个逗号前为百万（million），第三个逗号前为billion（十亿）。英语中无"万"这个词，我们可以用"几十个千（thousand）"表示几万，"几百个千（thousand）"表示"几十万"。如：2，510＝two thousand five hundred and ten；84，296＝eight-four thousand two hundred and ninety-six；274，350＝two hundred and seventy-four thousand three hundred and fifty。
二、序数词的构成
序数词一般是以与之相应的基数词尾加-th构成，例如 fourth, tenth,但以下的这些基数词变为序数词时， 有特别之处。
1.one--- first, two --- second, three --- third, five --- fifth, nice --- ninth, twelve --- twelfth
2. 以ty 结尾的单词， 要先变y为I, 在加-eth. 例如：thirty ---thirtieth, fifty ---fiftieth
3. 以one, two, three 等结尾的多位数词， 要将各位数变成序数词。 例如： twenty-one --- twenty-first, one hundred and one --- one hundred and first
注意： 序数词前常用定冠词， 有时还可以用不定冠词 a/an 则表示 "又一 "的意思。
例如：Mr Brown has a second car. 布朗先生另外还有一辆车。
He has tried a second time. 他又尝试了一次。
三、数词的应用
1．时刻的表示：小时、点钟、分钟、秒钟要用基数词。
①"几点钟"用基数词加o'clock。o'clock可省略。如： 5点钟-five（o'clock）．
②"几点过几分 "，≤30分钟"用介词past。如： 7：05-five past seven；7：15-fifteen （a quarter）past seven；7：30-half past seven。
③"差几分几点"用介词"to"。如：7：40-twenty to eight；7：45-fifteen（a quarter to eight。
④日常生活中的时间读法常常简化，直接按基数词的顺序读。如：7：05-seven o five；7：15- seven fifteen。
2．年月日的表示：
①年份用基数词，如：1999年-nineteen ninety-nine； 1900年-nineteen hundred； 2000-two thousand；1905-nineteen o five；
②年用基数词，日用序数词。如：1998年6月8日 写作：June 8，1998；读作：June the eighth， nineteen ninety-eight或the eighth of June， nineteen ninety-eight。
3. 世纪、年代表示法：
（在）90年代 (in) the nineties
（在）19世纪 (in) the nineteenth century
（在）18世纪30年代 (in) 1730s或1730's
4．编号的表示：
①Lesson One ＝the first lesson第一课；
②Bus No．3＝the No．3bus 3路公共汽车；
③表示住所时不用"No．"如：302房间-Room 302（读作：room three o two）；
④如果编号的数词比较长，一般用基数词。如：Page 457第457页；
⑤电话号码，用基数词,如：3855633-three eight five five（double five） six three three（double three）。
5．分数的表达：
分子用基数词，分母用序数词，分子大于"1"，分母则加"s"。如：1／3 one third，2／3two thirds；
另外：1／2 a（one）half; 1／4one fourth或a（one）quarter;3／4threefourths或three quarters。
half a second; a quarter of a second四分之一秒
6. 表示有小数的词用基数词。
5.5 five point five
12.135 twelve point one three five
7．表示百分数
5℅：five percent (per cent)， 0.8℅ zero point eight percent (per cent).
8．表示有小数的词用基数词。
5.5 five point five
12.135 twelve point one three five
9．其他用法：
1）基数词＋单数名词＋形容词构成合成形容词。如：一个五岁的男孩a five-year-old boy；
一座800米长的桥an 800-metre-long bridge；女子400米接力girls'400-metre relay race。
2）具体数词＋metre（s）／kilometre（s）／kilo（s）long ／ high ／tall ／deep ／away等。如：长江长6300公里。The Changjiang River is 6，300 kilometres long．
3）表示"几十岁"用序数词，eg. 在他三十几岁时 in his thirties
4）倍数的表达：(一倍用once，两倍用 twice，两倍以上用基数词＋times。如：5倍five times)。
例如：He is as tall a boy as I.
He is a head taller than I .
He is two years older than I
China is four times as large as Europe.
I am twice as old as you. (=I am twice older than you. /I am twice the age of you.)
My books are twice as many as yours.
China is four times larger than Europe.(=China is four times the size of Europe.)
I pay twice as much as it was worth.
I pay twice as much for the house.
例题解析：举一反三，学的更轻松！
1. _______ Chinese are looking for ways to learn English well before Beijing 2008 Olympic.
A. Thousand B. Thousands C. Thousand of D. Thousands of
2. Both of the rules are broken. I want to buy a ______ one.
A. three B. third C. forth D. /
3). --- Which is the smallest number of the four? --- _________.
A. Two- thirds B. A half C. A quarter D. Three-fourths
4). Please write down the new words in the text of _______.
A. Lesson Eleven B. the Lesson Eleven C. Lesson Eleventh
解析：1.基数词hundred, thousand, million, billion 等前有具体数字时，它们后面不能加s,若这些词后面有介词of (几百，成百上千) ，thousands of (几千，数千个)，millions of, billions of 前不可用数词修饰。但可用many, some, several 等修饰。故选答案D.
2．答案： B。此题主要考查序数词的运用。
3．答案：C。此题主要考查英语中的分数表示法。英语中表示分数时，分母用序数词，分子用基数词，当分子大于1时，表示分母的序数词后要加s.
4．答案： A。 此题主要考查基数词的编号。在通常情况下，名词编号有这几种表示法： 1。事物名词+基数词，且每个单词的首字母都要大写。如：Lesson Eleven；2。定冠词+基数词+事物名词。如： No. 6 Middle School
练习与巩固：熟能生巧，取得好成绩！
选择填空：
1._______ of people in the world are sending information by E-mail ever day.
A. Many million B. Several million C. Several millions D. Many millions
2.About _______ of the surface of the earth _______ covered with water.
A. three quarter, is B. three quarters, has C. three quarters, is D. three quarter, are
3.It will take _______ time to finish the work.
A. one and a half years' B. a year and half C. one and a half year's D. a year and half's
4．--- How long will your stay here ?、
---For ________ .
A. one and two day's B. one and two day C. a day or two D. one or two day
5．When he moved to Germany in ______ , he was already in _______ .
A. the fifties; his sixties B. fifties; his sixties
C. the fifties; his sixty D. fifty; sixty
6．My brother lives in ______ on ______ floor.
A. six Room ;second B. Room six ;the second
C. Room six; two floor D. the room six ; the second
7．December is _______ month of the year.
A. twelve B. twelfth C. the twelfth D. the twelve
8．This took place in the ______ .
A. 1940 B. 1940s C. 1940es D. 1940th
9．It is only _____ from my home to the train station.
A. ten minutes walk B. ten-minutes walk C. ten minutes 's walk D. ten minutes' walk
10．There are ______ in this building , I live on ______.
A. nine floors ,the ninth floor B. nine floor, the ninth floor
C. nine floor , nine floors D.ninth floor,the ninth floor
11．The water behind the Three Gorges Dams (三峡大坝) should be ______ higher than downstream（ 下游）。
A. sixty-five meter B. sixty-fifth meter
C. sixty-five meters D. sixty-fifth meters
12. There are _______ days in a year.
A. three hundred sixty-five B. three hundred and sixty-five
C. three hundred and sixty -five D. two hundreds and sixty-five
13. ---How many teachers are there in your school?
--- __________. , but I'm not sure.
A. Hundreds B. Hundred C. Hundreds of D. One hundred
14. There are _________ doctors and nurses working hard in that hospital.
A. thousand B. two thousand C. two thousands D. two thousands of
15. --- What's one fourth and a half, do you know?
--- Yes, it's _________.
A. two sixths B. three fourths C. one three D. three sixth
16. Now children, turn to page ________ and look at the _______ picture in Lesson Two.
A. twentieth, one B. twenty, one C. twentieth, first D. twenty, first
17. Both of the two rulers are broken. I want to buy a _______ one.
A. three B. third C. forth D. /
18. December is the __________ month in year.
A. twenty B. twelve C. twentieth D. twelfth
19. --- What is the date today?
--- It's _________.
A. Thursday B. June the sixteenth C. the best day D. June fifteen
20. She knows a lot about China as she has been to China ________.
A. for the forth time B. four times C. a fourth time D. for four times
1-5 CCACA 6-10 BCBD 11-15 CCCDA 16 -20 DBDBB
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