数词讲解

数词

1.定义与分类：数词是用来表示事物的数目和顺序的词，表示多少的词叫做基数词，one two three four 表示第几的词叫做序数词first second third fourth fifth sixth 等等。

2.作用：主语 宾语 表语 定语 状语 同位语 It is six there are six book Six is ok I want to buy six We six always get up early at six 注意数次作定语的用法:数词+名词（单数）+形容词 a five-year old girl

3.基数词的构成及其用法 英语中最基本的基数词有：

（2）其他基数词的构成

1）21-99十位个位之间要加连词符号（-）

2）101--999等三位数中十位数或个位数的前面加and . 101 one hundred and one 513 five hundred and thirteen 678 six hundred and seventy-eight

3）1000以上的数要用计数逗点，从个位开始每个三位数加一个逗点。

1

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

13 14 15 16 17 18 19

thirteen fourteen fifteen sixteen seventeen eighteen nineteen

20 30 40 50 60 70 80 90 100

twenty thirty forty fifty sixty seventy eighty ninety

one(a) hundred

23 35 101

twenty-three

thirty-five

one hundred and one

第一个逗点处是thousand 第二个逗点是百万million 第三个逗点处是十亿billion 。

1，000 4,596,786 18,458 怎么读？？怎么写？？

4）基数词常以单数出现但是当基数词用作名词时可有复数形式。 She has got three fives

数词hundred thousand million 前面有数词时表示确数不用复数形式，但是其后接of 短语所表示的一个约数时用复数形式。 Three hundred desks hundreds of desks

6)dozen 表示一打（12个）和 score （20个）也是一个量的单位，其前有具体的数字或者several 修饰时也不可加s 表示一个确数 ，但是当他们不与具体的数词或several 连用的时候要用复数表示约数。

Three dozen books dozens of books

4.序数词的构成及其用法

（1）一般序数词

1000th →one thousandth, 1000000th →one millionth., 第703→the seven hundred and third,

第5480→the five thousand four hundred and eightieth.

1st

2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th

※first

※second ※third fourth fifth sixth seventh eighth ninth

tenth

eleventh

twelfth

13th 14th 15th 16th 17th 18th 19th thirteenth fourteenth fifteenth sixteenth seventeent h eighteenth nineteenth 20th

30th 40th

50th 60th 70th 80th

90th

100th twentieth thirtieth fortieth fiftieth sixtieth seventieth eightieth ninetieth one undredth 21st 22nd 23rd 35th 101st

twenty-first twenty-second twenty-third

thirty-fifth

one hundred and first

（2）两位以上的序数词仅个位数部分用序数词,其余部分仍用基数词。如：thirty-sixth, forty-fifth

（3）使用序数词时一般加定冠词the. 如：I’m in the third grade. （4）序数词前有不定冠词a 表示再一又一的意思

A second time a third one

After eating two cakes ,he ate a third one .

5.分数的构成和用法

分子用基数词，分母用序数词，分子是1时分母用单数，分子是2 时分母用复数。1/2可以用half 表示，四分之一可以用quarter表示。读带分数时，先读整数部分，再读分数部分，中间用and 连接。1/5→one fifth ; 2/3→two thirds ; 4/7→four sevenths ; 1/2→a half ; 1/4→a quarter ; 3/4→three quarters ; 50%→fifty hundredths ( fifty per cent).32⅜ thirty-two and three eighths

6.小数的构成及用法

整数与小数之间用小数点隔开，读小数时每位数字要单独读出，小数点读point 0读zero 。0.1 zero point one 0.03 zero point zero three 2.25 two point two five 14.163 fourteen point one six three

注意：1）和带分数连用的名词用复数

2）如果带分数的整数部分是1 名词在带分数之后用复数，名词在1和分数之间时，名词要用单数。

One apple and a third one and one third apples .

3）与小数连用的名词，整数是零时名词用单数，其他情况名词要用复数。

7.百分数的构成和用法

5% 5 per cent 22% twenty-three per cent

8.倍数的构成及其用法

1）倍数的表达法

2倍twice double 3倍three times triple 4 倍及以上：基数词+times

2）倍数比较的表达法

a A be数+as+原级adj adv +asB This desk is as big as that one .

b A be 数+times + 比较级+ than B This desk is three times bigger than that one .

c A be 数times +the +n（length height size weight breadth value ）of B This desk is three times the size of that one .