数词表示数目多少或顺序多少。作主、宾、表语和定语。分基数词和序数词。基数词表示数目:one,two,three…
序数词表示顺序:first,second,third…序数词前一般要加the
基数词
序数词1-10first second third fourth fifth sixth seventh eighth ninth tenth
11-20eleventh twelfth thirteenth fourteenth fifteenth sixteenth seventeenth eighteenth nineteenth twentieth
21-30twenty-first twenty-second twenty-third twenty-fourth twenty-fifth twenty-sixth twenty-seventh twenty-eighth twenty-ninth thirtieth
31-40thirty-first thirty-second thirty-third thirty-fourth thirty-fifth thirty-sixth thirty-seventh hirty-eighth thirty-ninth fortieth
41-50forty-first forty-second forty-third forty-fourth forty-fifth forty-sixth forty-seventh forty-eighth forty-ninth
基数词序数词
1
one 第一first 1st10,000
ten thousand一万
2
two 第二second 2nd100,000
one hundred thousand十万
3
three 第三third 3rd1,000,000
one million一百万
4
four 第四fourth 4th1,000,000,000
Billion/a hundred million亿
5
five 第五fifth 5th
6
six 第六sixth 6th
7
seven 第七seventh 7th
8
eight 第八eighth 8th
9
nine 第九ninth9th
10
ten 第十tenth 10th
11
eleven第十一eleventh11th
12
twelve第十二twelfth12th
13
thirteen第十三thirteenth13th
14
fourteen 第十四fourteenth14th
15
fifteen第十五fifteenth15th
16
sixteen第十六sixteenth16th
17
seventeen第十七seventeenth17th
18
eighteen第十八eighteenth18th
19
nineteen第十九nineteenth19th
20
twenty第二十twentieth20th
30
thirty第三十thirtieth30th
40
forty第四十fortieth40th
50
fifty第五十fiftieth50th
60
sixty第六十sixtieth60th
70
seventy第七十seventieth70th
80
eighty第八十eightieth80th
90
ninety第九十ninetieth90th
100
one hundred第一百one hundredth100th
900
nine hundred第九百nine-hundredth900th
1000
one thousand第一千one thousandth1000th
1001
one thousand and one第1001one thousandth and one1001st
21-99用十位整数加上个位整数，用“一”连接twenty-one forty-six ninety-five
101-999个数基数词形式加“hundred”，表示几百，在几十几与百位间加上and101 a hundred and one 320 three hundred and twenty
千位数以上从数右端向左数每3位数加个“，” 第一个“，”前的数字后加thousand2,648 two thousand six hundred and forty-eight
第二个“，”前面的数字后加million5,237,166,234 five billion，two hundred and thirty-seven million，one hundred and sixty-six thousand，two hundred ,and thirty-four
第三个“，”前的数字后加 billion
然后一节一节分别表示，两个逗号间最大的数为百位数形式
数字：表示确切数字时，不能用百、千、百万、十亿的复数形式；但当基数词表示不确切数字，如成百、成千上万，三三两两时，基数词则以复数形式出现
There are hundreds of people in the hall大厅里有数以百计的人。
Thousands and thousands of people come to visit the Museum of Qin Terra-Cotta Warriors and Horses every day． 每天有成千上万的人来参观秦兵马涌博物馆
They went to the theatre in twos and threes他们三三两两地来到了剧院。
人不确切岁数或年代，用几十的复数形式 He became a professor in his thirties．他三十多岁时成为了教授。
She died of lung cancer in forties．她四十来岁时死于肺癌。
It was in the 1960s．那是在二十世纪六十年代。
句法功能：句中可作主语、宾语、定语、表语、同位语。
The two happily opened the box．两个人高兴地打开了盒子。 （作主语）
I need three altogether．我总共需要三个。 （作宾语）
The city has population of four million这个城市有四百万人口 （介词宾语）
Four students are playing volleyball outside．四个学生在外面打排球。 （作定语）
We are sixteen．我们是16个人。 （作表语）
They three tried to finish the task before sunset．他们三个人尽力想在日落前完成任务 （作同位语）
approximately [əˈprɑːksɪmətli] （a p rua k 丝门李） adv.大概;大约;约莫
数学公式的读法3+8=11 Three plus eight is eleven
9-7=2 Nine minus seven is two
6x5=30 Six times five （six multiplied by five) is thirty 乘以;(用于比较)倍
8÷4=2 Eight divided by four is two
a＞b a is more than b
a＜b a is less than b
a≈b a approximately equals to b [əˈprɑːksɪmətli] （a p rua k 丝门李） adv.大概;大约;约莫
a≠b a is not equal to b
表示时刻用基数词
We get up at six. The workers begin work at eight.
几点过几分用介词past,但须在半小时以内ten past ten十点十分 a quarter past nine九点一刻 half past twelve十二点半
几点差几分用介词to, 但分数须在半小时以上twenty to nine 8点40分 five to eight 7点55分 a quarter to ten差一刻十点
几点几分还可直接用基数词seven fifteen七点十五 eleven thirty十一点三十
(1)序数词主要用作定语，前面要加定冠词theJohn lives on the fifteenth floor．约翰住在十五楼
(2)序数词有时前面可加不定冠词表示“再一”，“又一”意思We'll have to do it a second time．我们得重做一遍
Shall I ask him a third time？ （我已经问了他两次）还要问一次吗？
When I sat down，a fourth man rose to speak．我坐下后第四个人又起来发言
(3)表示年，月，日时， 年用基数词表示，日用序数词表示1949年十月一日读作: October (the) first, nineteen sixty
2004年九月十日读作：September (the) tenth, two thousand and four
first，second等词有时可用来代表“第一个（批）” “第二个人” She was among the first(few) to come and settle in Tuckiashan她是第一批来杜家山安家落户的
如果数字较长，序数词总是避免使用，而且读的方法也常常简化 Page 319 三号和四号卧铺Berths Nos 3 and 4 延安路1378 1378 Yenan Road
1)年份用基数词,日期用序数词。1988年5月1日可以写作 May 1(st),1988，读作May the first,nineteen eighty-eigh
2)英语年份的读法：一般先读前两位数,再读后两位数。 1983→nineteen eighty-three? 1700→seventeen hundred? 1601→sixteen a one或sixteen hundred and one?
注意. ①日期可全用阿拉伯数字,英、美写法不同。英先写日子,美先写月份。 例如：6,8,1988=1988年8月6日(英国)?=1988年6月8日(美国)?
②年份的后面不用year(年),但有时前面有用year, 如in the year 1949(读作in the year nineteen forty-nine)
③公元前的年份后面加 B.C.(用before Christ第一个字母,公元前)。 如221. B.C. 可读作two twenty-one B.C.。
公元后年份一般在后面加A. D.(拉丁语Anno Domini的第一个字母,in the year of the Lord,是公元)。有时也有把A. D.加在前面的,如A. D. 1949(=1949.A. D.)
3)年代用年份的阿拉伯数字加-’s 或-s表示。例如：十八世纪三十年代→1730’s/1730s?the seventeen thirties?
序数词句法：序数词在句中可作主语、宾语、定语和表语The second is what I really need．第二个是我真正需要的。（作主语）
He choose the second．他挑选了第二个。（作宾语）
We are to carry out the first plan．我们将执行第一个计划。（作定语）
She is the second in our class．在我们班她是第二名。（作表语）
注：序数词在使用时，通常前面要加定冠词 the；但是如果序数词前出现不定冠词a或an时，则表示“再——”，“又——”。
We'll go over it a second time．我们得再念第二遍。
We've tried it three times．Must we try it a fourth time? 我们已经试过三遍了，还必须试一次（第四次）吗？
另外，基数词也可以表示顺序。只需将基数词放在它所修饰的名词之后即可，不需要添加定冠词。
the first lesson一Lesson One the fifth page一Page 5（five） the twenty-first room一Room 21(twenty-one）
1.分数：分子用基数词，分母用序数词，如分子大于1，分母用序数词的复数形式。中间的连字符可用可不用one-fourth，seven-ninths，two and three-fifths，thirty and seven-eighths
You spend one-second of the monthly expense on body-building .你将月开销的二分之一用于健身运动。
分数词的特殊表示法。1/2 a(one) half，1/4 a （one）quarter，3/4 three-quarters，
2 1/4two and a quarter，1 1/2one and a half，
22/9 twenty-two over nine 33/89 thirty-three over eighty-nine
My bag is at least 2 1/2 times the weight of yours.我的包至少是你们的两倍半重。
I give you one half, and keep the other half for myself.我给你们一半，自己留了另一半。
She used one-third of her income on clothing.她把自己三分之一的收入用于服装。
Some $30 million, about one-sixth of the total budget, was spent on medical care last year去年约占总预算六分之一的三千万美元用于医疗保健
This laptop computer is only one-tenth the weight of a normal desk-top computer.这台膝上型电脑仅是一台普通桌上型电脑的十分之一重
结构“分数词+of+名词”表示“某整体的几分之几” Two fifths of the land is covered with trees这片土地的五分之二覆盖着森林
分数在句子中可作主语、宾语或介词的宾语、同位语或表语、定语、状语
主语： A quarter of the workers are women四分之一的工人是女工
宾语或介词的宾语：The kang takes up two-thirds of the space炕就占了三分之二
同位语或表语： some 255 million people,about two-fifths of our population live in this immense area约占我国人口五分之二的二亿五千万人居住在这个辽阔的地区
定语： The mass of an electron is 1/1850 that of a hydrogen atom电子的质量是氢原子质量的1850分之一
状语： China is one-sixth larger than the United States中国比美国大六分之一
2.小数的读法：7.8 seven point eight ；0.03(nought)point nought three或zero point zero three；14.397one four point three nine seven；603.09six oh three point oh nine
小数作定语时较多：Its capacity was 7.3 times as great as in 1955它的生产能力为一九五五年生产能力的7.3倍
3.百分数由per cent，常和by连用，作状语The price was cotton went up by 20 per cent它的棉花产量增长了百分之二十
The loss of metal has been reduced to less than 20%金属损耗减少到百分之二十以下
数词表示倍数主+谓+倍数（或分数）+ as + adj. + asI have three times as many as you 我有你3倍那么多
主+谓+倍数（或分数）+ 形容词（副词）+the size（amount，length…)of…The earth is 49 times the size of the moon地球是月球的49倍
主+谓+倍数（或分数）+ 形容词（副词）+比较级 +thanThe grain output is 8 percent higher this year than that of last year今年的粮食产量比去年高8%
by +倍数，表增加多少倍The production of grain has been increased by four times this year今年粮食产量增加了四倍
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