第13章 数词一.概念: 数词分两类:基数词和序数词.表示数目的词叫基数词,表示须序的词叫序数词.二.相关知识点精讲 1.基数词1）基数词一般可写成如345或three hundred and forty-five。2）基数词一般是单数形式，但遇下列情况，常用复数： a. 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； b. 在一些表示一排或一组的词组里。例如：They arrived in twos and threes.他们三三两两的到了。 c. 表示几十岁。 d. 表示年代，用 in +the +数词复数。 e. 在乘法运算的一种表示法里，如Three fives is（are）fifteen。2.序数词 序数词的缩写形式如first-1stsecond-2ndthirty-first-31st等。3.数词的用法1）倍数表示法 a. 主语+谓语+倍数（或分数）+ as + adj. + as。例如 I have three times as many as you.我有你三倍那么多。 b. 主语+谓语+倍数（分数）+ the size （amount，length） of。例如： The earth is 49 times the size of the moon.地球是月球的49倍。 c. 主语+谓语+倍数（分数）+ 形容词（副词）比较级+ than。例如： The grain output is 8 percent higher this year than that of last year. 今年比去年粮食产量增加8%。 d. 还可以用by+倍数，表示增加多少倍。例如： The production of grain has been increased by four times this year. 今年粮食产量增加了4倍。2）分数表示法的构成：基数词代表分子，序数词代表分母。分子大于1时，分子的序数词用单数，分母序数词用复数。例如： 1/3 one-third； 3/37 three and three-sevenths.三.巩固练习 1._ martyrs have heroically laid down their lives for the people.a. Thousand upon thousand of b. Thousand and thousands ofc. Thousands upon thousands of d. Thousand and thousand of2.They received _ of letters about their TV programs.a. dozen b. dozen and dozen c score d. dozens3.Who is that man,_ in the front row?a. one b. the one c. first d. the first4.We have produced _ this year as we did in 1993.a. as much cotton twice b. as twice much cottonc. much as twice cotton d. twice as much cotton5.The earth is about _ as the moon.a. as fifty time big b. fifty times as big c. as big fifty time d. fifty as times big6.The population of many Alaskan cities has _ in the past three years.a. more than doubled b. more doubled than c. much than doubled d. much doubled than7.The moon is about _ in diameter as diameter as the earth.a. one-three as large b. one three as large c. one-third as large d. one third as large8.Five hundred yuan a month _ enough to live on.a. is b. are c. is being d. has been9._ of the buildings were ruined.a. Three fourth b. Three four c. Three-fourths d. Three-four10.Consult _ for questions about earthquakes.a. the six index b. index six c. sixth index d. index numbering six四.答案 CDDDBACACB