数词(Numeral),简称(num),是指表示数目多少或顺序多少的词。
1、用法
英语的数词可以作句子的主语、宾语、表语和定语。
2、分类
数词分为两大类,即基数词和序数词。基数词表示数目,序数词表示顺序。
基数词一般是单数形式,但下列情况,常用复数:
(1)与of短语连用,表示概数,不能与具体数目连 用,如:scores of people 指许多人。
(2)在一些表示"一排"或"一组"的词组里,如:
They arrived in twos and threes. 他们三三两两的到达了。
(3)表示"几十岁"为dozens of ages。
(4)表示"年代",用 in the 数词复数。
(5)在乘法运算的一种表示法里,如:
3 x 5 = 15 Three fives is (are) fifteen.
3、基数词及其用法
(1)基数词 1-12 是独立单词,需逐个记忆。
one,two,three,four,five,six,seven,eight,nine,ten,eleven,twelve
(2)基数词 13-19是个位数词的词干后加-teen 构成。其中 thirteen, fifteen, eighteen 变化不规则。
thirteen,fourteen,fifteen,sixteen,seventeen,eighteen,nineteen
(3)基数词 20-90 是在个位数词后面加 -ty 构成。其中 twenty, thirty, forty, fifty, eighty 变化不规则。
twenty,thirty,forty,fifty,sixty,seventy,eighty,ninety
(4)基数词 21-99 是在十位数词后面加上个位数词合成,中间加上连字符 " - " ,如:
21 twenty-one,95 ninety-five
(5)百、千、十万、十亿
a hundred,a thousand,a million,a billion
(6)基数词三位以上的数词, 在百位和十位之间,一般要用连词"and ",十万位和万位,亿位和千万位之间通常也要加and,如:
132 one hundred and thirty-two
1340 one thousand three hundred and forty.
英语中没有万,千万,亿这样的单位数词,ten thousand 十千=一万。
用阿拉伯数字书写千以上的数目时,要由右向左每三位数间留一个空格或写一个逗号。第一个前为thousand;第二个前为million;第三个前为thousand million(英)或billion(美)。每两个空格间或两个逗号间的三位数都被看作“十位数或百位数的千”或“十位数或百位数的百万”,如:
56 000 fifty-six thousand
600,000,000 six hundred million。
dozen,score,hundred,thousand,million等数词前面有基数词或某些表示数量的形容词时,不加-s,如 :
a few hundred meters 几百米
several million people 数百万人
two thousand teachers 两千位老师
但如果表示“几百”“几千”“几百万”等笼统的数目时,则应用“复数 of”构成短语,如:
hundreds of books 几百本书
thousands of workers 几千个工人
hundred、 thousand、 million作数词时,不用复数,前面可以加上one, two, …等其它数词。用作名词时复数表示“成…上…”,后面必须要有of,前面可以加上some,many,several等词,如:
five hundred(五百)
hundreds of(成百上千的)
ten thousand(一万)
thousands of(成千上万的)
millions of(成百万的)
4、基数词的使用位置
(1)位于another,all之后,如:
Can you have another two cakes? 你还能吃2块蛋糕吗?
The boy lost all the five pencils last week.这孩子上周把5枝铅笔全丢了。
(2)位于such和more之前如:
I can finish reading two such books in two days.两天里我能读完这样的两本书。
Please give me one more apple to eat.请再给我一个苹果吃。
(3)可置于last,next,other之前或之后,如:
His last two books are written in English.他的后两本书是用英语写的。
5、序数词及其用法
(1)序数词的缩写形式为阿拉伯数字加序数词的最后两个字母,如:
first---1st;second---2nd; third-3rd;thirty-first---31st
(2)基数词变序数词口诀
一,二,三要全变,如:
one-first; two-second;three- third
其余都加th, th里有例外,8去t,(eight-eighth) 9去e(nine-ninth)字母f代ve(five-fifth; twelve-twelfth)
ty变成tie(twenty-twentieth)
若要变化几十几,只变个位就可以(twenty-one-twenty-first)
6、基数词的用法
(1) 作定语、如:
There are only three boys in the class. 班上只有3名男生。Ten people will come to the party. 十个人要来参加聚会。
(2) 作主语,如:
It is said that thirteen is an unlucky number. 据说13是个不吉利的数字。
Three of them will play football. 他们中有三人要去踢足球。
(3) 作宾语,如:
It is worth three hundred. 这件东西值300。
The city has a population of three million. 这个城市有三百万人口。
(4) 作表语,如:
I am eighteen. 我18岁。
Two and two is four. 二加二等于四。
(5) 作同位语,如:
Are you two coming? 你们俩来吗?
They ten will go abroad. 他们十个人将出国。
(6)有时序数词前面可加不定冠词来表示“再一”,“又一”这样的意思,如:
We'll have to do it again. 我们得重做一次。
Shall I ask him a third time? 还要再问他一次吗?
When Nash sat down, a fourth man rose to speak.纳什坐下后,第四个人又起来发言。
(7)作表语时,序数词前的定冠词往往省去,如:
Lynd was second last year. 林德去年是第二。
7、在很多情况下,可以用基数词代替序数词来表示顺序,如:
the second part = Part two (第二部分)
the first chapter = Chapter one (第一章)
the fourth section = Section four (第四节)
8、倍数表达法
()1)基数词 倍数 形容词/副词比较级 than,用…times表示,如:
The girl is ten times cleverer than her brother.
(2)如果表示“是……两倍数”,一般用twice,如:
My room is twice as large as yours.
(3)基数词 倍数 as 形容词/副词/名词 as,如:
His apartment is three times as large as that of mine.
Americans eat twice as much protein as they actually need every day.
My aunt is as old age as I am. 我姑姑年龄和我一样大。
(4)基数词 倍数 名词,如:
The volume of the Sun is about 1,300,000 times that of the earth.太阳的体积约为地球的1300000倍。
(5)动词 基数词 倍数,用-fold或基数词加times表示,如:
The value of the stock has increased two-fold since we bought it.
Productivity is increased three fold. 生产效率提高了两倍。
The pants have shortened two times since they were bought.
(6)用double(翻一番)
2023.03.31