二、序數(shù)詞

序數(shù)詞的縮寫形式： first——1stsecond——2ndthirty-first——31st

三、 數(shù)詞的用法

1)倍數(shù)表示法

a. 主語+謂語+倍數(shù)(或分?jǐn)?shù))+ as + adj. + as

I have three times as many as you.我有你三倍那么多。

b. 主語+謂語+倍數(shù)(分?jǐn)?shù))+ the size (amount，length…) of…

The earth is 49 times the size of the moon.地球是月球的49倍。

c. 主語+謂語+倍數(shù)(分?jǐn)?shù))+ 形容詞(副詞)比較級(jí)+ than…

The grain output is 8 percent higher this year than that of last year.

今年比去年糧食產(chǎn)量增加8%.

d. 還可以用by+倍數(shù)，表示增加多少倍

The production of grain has been increased by four times this year.

今年糧食產(chǎn)量增加了4倍。

2)分?jǐn)?shù)表示法

構(gòu)成：基數(shù)詞代表分子，序數(shù)詞代表分母。分子大于1時(shí)，分子的序數(shù)詞用單數(shù)，分母序數(shù)詞用復(fù)數(shù)：

1/3 one-third ; 3/37 three and three-sevenths.