实用英语语法教程-第十章-数词课件.ppt

1、第十章第十章 数词数词 o 1数词的用法o 2.常用数的表示法1.数词的用法1.1 基数词（1）在句中可用作主语、宾语、表语、定语和同位语等。例如：Five of them went to the cinema.（主语）I want three.（宾语）We are altogether twenty.（表语）I have invited ten people to the party.（定语）They three went together.（同位语）（2）数词在与名词连用作定语时，通常中间有连字符，且只用名词的单数形式。例如：a ten-pound note a twenty-page p

2、amphlet（3）基数词本身没有复数形式（由基数词构成的固定短语除外）。例如：five hundred soldiers 但在一些固定用法中，如“成百上千，成千上万等中，基数词要用复数形式。例如：hundreds of students 数百名学生 thousands of birds 数千只鸟 tens of thousands of成千上万的 millions of 数百万1.2 序数词（1）在句中可用作主语、表语、宾语、定语、同位语和状语等。例如：The second is mine.（主语）Mary was the fourth to arrive.（表语）Give me the t

3、hird.（宾语）He is the last person to tell a lie.（定语）Who is that man,the first in the front row?（同位语）Where did you first meet her?（状语）（2）序数词与定冠词the搭配，可起名词词组的作用。例如：Mike will be the first to speak at the meeting,and you the second.He was among the first who collected Picasso paintings.（3）序数词还可以用作副词，例如：I f

4、irst went to Paris,and then to New York.She came out second in the penmanship competition.（4）序数词前通常要用定冠词the,但有时也可用不定冠词a 或an，其含义为“又一”，“再一”。例如：Well have to do it a second time.Shall I ask her a third time?1.3 由数词构成的常用固定短语（1）由基数词构成的固定短语有：by/in twos and threes 三三两两，零零星星one in a thousand 难得的人或物，出类拔萃ten t

5、o one 十有八九，很可能at one time 一度by fours and fives三五成群（2）由序数词构成的固定短语有：second to none 首屈一指，比谁都好at first sight/glance乍一见，初看起来on second thoughts 经过重新考虑first of all 首先think twice 仔细考虑，深思熟虑First come,first served.先到先招待。（或：捷足先登）1.4 使用数词应注意的问题（1）基数词的主谓一致问题应遵循的规则为：基数词+名词+动词单数。例如：Fifty yuan is not enough.Five po

6、unds doesnt buy as much as it used to.Five thousand miles is a long distance.5000 Eight hundred dollars a month for rent was more than I could afford.（2）more与基数词连用时的词序为：基数词 在more之前。例如：We need two more students.（3）基数词+dozen或score时，dozen和score用单数形式。例如：Two dozen(of)eggs.Three score(of)police Id like to

7、 take two dozen of these tomatoes.2常用数的表示法 2.1 编号可用基数词置于名词后或序数词置于名词前（要加the）。例如：Unit One/the first unit第一单元Chapter Two/the second chapter第二章2.2 日期、时间、年龄、长度、宽度、高度等in the 1990s(1990s)在20世纪90年代（读为in the nineteen nineties）She is 25(years old)/at the age of 25.她25岁。about ten miles long/about ten miles in

8、length 大约10英里长twenty meters wide/twenty meters in width 20米宽2.3 分数、小数、百分数（1）表示分数时，分子用基数词，分母用序数词，除了分子是“1”的情况，分母的序数词都要用复数形式。例如：1/3 a(one)-third 1/4 a(one)-fourth,a(one)quarter 3/5 three-fifths 23/5 two and three-fifths（2）小数以基数词加小数点表示。读小数时，小数点前面的数按基数词的规则读，小数点后面的数按个位基数词依次读出。例如：3.12 three point one two 0

9、.007 zero point zero zero seven(其中的zero也可读作nought或oh)（3）百分数由基数词或小数加百分号组成。例如：90%ninety percent（或percent）1.28%one point two eight percent(或percent)Genius is one percent inspiration and ninety-nine percent perspiration.天才是百分之一的灵感，加上百分之九十的汗水。（4）分数和百分数作主语时，谓语动词的数由其表示的实际意义来决定。例如：Eighty percent of the work

10、 has been done.More than ninety percent of the students have passed the exam.2.4 倍数表示法（1）用“times+as+形容词/副词+as”结构。例如：China is ten times as large as Japan.中国有日本十倍大。Americans eat twice as much protein as they actually need every day.美国人每天所摄取的蛋白质是他们实际所需的两倍。（2）用“times/百分比+比较级+than”结构。例如：This dictionary i

11、s three times thicker than that one.这本词典是那本词典的三倍厚。Output of strip steel this year was 29 percent higher than that of last year.今年带钢产量比去年提高29%。（3）用“times+the+名词”结构。例如：This reservoir is five times the size of that one.这个水库是那个水库的五倍大。Nigeria is three times the size of Great Britain.尼日利来比英国大两倍。注 这一结构中，常见

12、的名词除size外，还有capacity,distance,length,number,output等一些表示大小或数量的名词。（4）用“times+what引导的分句“。例如：Output is now six times what it was before 1990.现在的产量是1990年以前的六倍。（5）用“动词+（by）+times/百分比”结构。例如：The grain output has increased(by)5 times.粮食产量增加了五倍。Population has increased by 200%in the past 25 years.人口在过去25年内增加了

13、200%。（6）用表示倍数的动词来表示。例如：The Federal government has doubled its tax on liquor.联邦政府把酒税提高了一倍。The company has tripled in size in the last twenty years.在最近20年里，该公司在规模上已扩大了两倍。2.5 与“半”相关的表达法 a half million dollars/half a million dollars 50万美元 a half hour/half an hour半小时 two and a half hours/two hours and a

14、half 两个半小时 Half the apple is good./Half the apples are good.这个苹果一半是好的。/这些苹果一半是好的。2.6 常见的数学符号表示法“=”读作equal,is equal to,is,are,make,makes等“+”读作plus或and “-”读作minus“”读作times或multiplied by “”读作divided by“”读作divided by 试比较下列各种同义表达法：6-3=3 读作Six minus three/Three from six equals/makes/is three.3+3=6读作Three

15、plus/and three are/is/equal/equals/make makes six.33=9读作Three times(或multiplied by)three is/equals nine.93=3读作Nine over(或divided by)three is/equals three.练习答案与解析1.B.数词在与名词连用作定语时，通常中间有连字符，且只用名词的单数形式。2.C.表示长度：数词+单位词+long/in length,如果数词是复数，相应地单位词也应为复数。3.A.in ones thirties指某人三十多岁；in ones fifties指某人五十多岁。

16、4.A.一个半小时：one and a half hours，one hour and a half或者an hour and a half都可以。5.B.倍数可用“times/百分比+比较级+than”结构表示；此外可：用“times+as+形容词/副词+as”结构；用“times+the+名词”结构；用“动词+（by）+times/百分比”结构；用表示倍数的动词来表示。6.C.Tens of thousands of years成千上万年；A.B的 正确形式应该是several million years。7.B.当句子主语为百分数+名词，谓语动词由百 分数后面名词的数来决定。8.B.by

17、 twos and threes为固定搭配，意为“三 三两两”。9.C.a third time再一次。10.C.“三十到四十”可用“more than thirty and less than forty”或“thirty odd”表示。11.A.倍数的一种表示方法可用“times+the+名词+of”结构。12.B.twice as likely as可能性是两倍。13.C.表示分数时，分子用基数词，分母用序数词，除了分子是“1”的情况，分母的序数词都要用复数形式。当句子主语为“分数+名词”时，谓语动词由分数后面名词的数来决定。14.D.表示半个蛋糕用“half the cake”。15.A.倍数的一种表示方法可用“times+the+名词+of”结构。16.C.本句倍数的表示法用twice as many cars as结构。17.B.倍数的一种表示法：用“times+as+形容词 副词+as”结构。18.B.本句中 cost twice as much as 表示“花费是 的两倍”。19.C.倍数可用“times+比较级+than”结构表示。20.D.in the first place“首先”，是固定短语。句意为 “在我看来，首先我们的计划就行不通。”