二、序數詞

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

三、 數詞的用法

1)倍數表示法

a. 主語+謂語+倍數(或分數)+ 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(分數)+ 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(分數)+ 形容詞(副詞)比較級+ than…

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

今年比去年糧食產量增加8%.

d. 還可以用by+倍數，表示增加多少倍

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

今年糧食產量增加了4倍。

2)分數表示法

構成：基數詞代表分子，序數詞代表分母。分子大于1時，分子的序數詞用單數，分母序數詞用復數：

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