序数词的用法 (1)序数词主要用作定语,前面要加定冠词,例如: The first truck is carrying a foot baskets. John lives on the fifteenth floor. (2)序数词有时前面可加不定冠词来表示“再一”,“又一”这样的意思,例如: We'll have to do it a second time. Shall I ask him a third time? When I sat down,a fourth man rose to speak. (3)由几个序数词和基数词在拼写时不对应,很容易写错,应特别注意。它们是:one---first, two---second, three---third, five---fifth, eight---eighth, nine---ninth, twelve---twelfth。 (4)表示年,月,日时, 年用基数词表示,日用序数词表示。例如: 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 (5)表示分数时,分子用基数词表示,分母用序数词表示。分子大于1时,分母加-s。例如: three fourths, one second, two fifths (6)序数词有时用缩写形式: first→1st second→2nd third→3rd fourth→4th twenty-second→22nd
数词的用法 1)倍数表示法 a. 主语+谓语+倍数(或分数)+ as + adj. + as 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… 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… 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 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 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: 1/3 one-third ; 3/37 three and three-sevenths.
注意事项: 三位数数词要在百位和十位(若无十位则和个位)之间加and。 1,000以上的数字,从后向前第三位数加一个“,”,第一个“,”前为thousand,第二个“,”前为million,第三个“,”前为billion。 2.序数词除了first,second,third外,其余都在基数词尾加-th构成。 3.分数分子在前,分母在后,分子用基数词,分母用序数词,当分子大于1小时,分母序数词要变成复数。 4.Hundreds(thousands,millions)of……用法。