基数词在句中的作用

从句子成分上分析，基数词在句中可用作主语，宾语，定语，表语等。

(1) 主语
Two will be enough. 两个就够了。
Three of the students were late yesterday. 昨天有三个学生迟到了。

(2) 宾语
I read four of her novels. 我看了她写的四本小说。
Give me two. 给我两个。
The city has a population of three million. 这座城市有三百万人口。

(3) 定语
There are nineteen students in our class. 我们班有十九个同学。
The river is about eighty miles long. 这条河大约八十英里长。

(4) 表语
She is just fourteen. 她刚十四岁。
He was already forty when he began to learn English. 他开始学英语时已经四十岁了。

(5) 同位语
You two will go swimming with us. 你们两个将和我们去游泳。
You may leave it to us three. 你可以将这事交给我们三人去做。