定義：表示數目多少或順序多少的詞叫數詞，數詞分為基數詞和序數詞。表示數目多少的數詞叫基數詞；表示順序的數詞叫序數詞。

I基數詞

1.基數詞的構成

（1）1-20

one,two,three,four,five,six,seven,eight,nine,ten,eleven,twelve,thirteen,fourteen,fifteen, sixteen, seventeen, eighteen, nineteen, twenty

（2）21-99 先說“幾十”，再說“幾”，中間加連字符。

23→twenty-three,34→thirty-four,45→forty—five,56→fifty-six,67→sixty-seven,78→seventy-eight,89→eighty-nine,91→ninety-one

（3）101—999先說“幾百”，再加and,再加末兩位數或末位數；

586→five hundred and eighty-six,803→eight hundred and three

（4）l,000以上,先從右往左數，每三位數加一個“,”,第一個“,”前為thousand.第二個“,”前為

million,第三個“,”前為billion（美式）或thousand ,million（英式）,然后一節一節地表示。

1,001→one thousand and one

9,785→nine thousand, seven hundred and eighty-five

18,423→eighteen thousand, four hundred and twenty-three

6,260,309→six million two hundred and sixty thousand three hundred and nine

750,000,000,000→seven hundred and fifty, billion（美式） seven hundred and fifty thousand million（英式）