数词专题讲解知识清单-2024届高三英语一轮复习

数词专题

一、基数词与序数词

基数词	序数词	基数词	序数词
one	1st  = first	twenty-one	21st=twenty-first
two	2nd = second	twenty-two	22nd= twenty-second
three	3rd = third	twenty- three	23rd=twenty-third
four	4th=fourth	thirty	30th=thirtieth
five	5th=fifty	forty	40th=fortieth
six	6th=sixth	fifty	50th=fiftieth
seven	7th=seventh	sixty	60th=sixtieth
eight	8th=eighth	seventy	70th=seventieth
nine	9th=ninth	eighty	80th=eightieth
ten	10th=tenth	ninety	90th=ninetieth
eleven	11th=eleventh	one hundred	100th=one hundredth
twelve	12th=twelfth	one hundred and one	101th=one hundred and first
thirteen	13th=thirteenth	one hundred and two	102nd=one hundred and second
fourteen	14th=fourteenth	three hundred	300th=three hundredth
fifteen	15th=fifteenth	one thousand	1000th=one thousandth
sixteen	16th=sixteenth	three thousand	3000th=three thousandth
seventeen	17th= seventeenth	ten thousand	10000th=ten thousandth
eighteen	18th= eighteenth	one million	1000000th=one millionth
nineteen	19th= nineteenth	one billion	1000000000th=one billionth
twenty	20th=twentieth

序数词变化规律：

1. 整十的序数词表示: 第20、30、40、50、60、70、80、90 是将基数词词尾y 变为i 加-eth.
2. 非整十的序数词表达：其他非整十的序数词仅把个位数变为序数词，十位不变。
3. 100和100以上的表示：

100写为: 100th : 读为：  one hundredth

101写为：101st  读为：one hundred and first

二、小数

1. o.5: 读作：zero point five
2. 1.6 读作：one point six

三、分数

1. 分子用基数，分母用序数。分子大于一，分母加-s.

eg: 3/5 :读作：three fifths

eg: 1/6 : 读作：one sixth

2. 用介词in = out of 来表达

eg: 5/6 : five in six = five out of six

3. 一半：half
4. 四分之一：quarter

   四分之三：three quarters = three fourths

四、百分数

1. 21% :  twenty-one  percent
2. 0.5% : zero point five percent

五、数词表达确切数字。

表达确切数量直接用基数词或分数、小数、百分数等

hundred，thousand，million，billion等前有具体数词修饰时，这些词不能用复数形式.

eg: The number of cars in our city is increasing by two hundred a day.

我们城市汽车的数量正以每天两百辆的速度增加.

eg: Three fifths of the population voted for him.

五分之三的人投票支持他.

六、数词表达不确切数量

ten，hundred，thousand million，billion等可以构成短语,表达不确切的数量。此时，这些词用复数且与of 连用，不能用具体数字修饰，可用many，several，a few等。

tens of  数十的

hundreds of  数百的

tens of thousands of  成百上千的

thousands of       数千的

millions of  数百万的

hundreds of millions of  成百万的

a few hundreds of  数百的

several  thousands of   数千的

many millions of       好几百万的

eg: three score years : 六十年

eg: two dozen eggs两打鸡蛋

eg: scores of people几十个人

eg: dozens of books几十本书

eg: several dozen people数十人

eg: a score of them他们中的二十个

eg: a dozen of them他们中的十二个

eg: two score of these books这些书中的四十本

eg: two dozen of these books这些书中的两打      

注意： 特殊表达：score （二十），decade（十年）， quarter （四分之一）， dozen （十二），