序数词在句中的作用

序数词在句子中可用作下列各个句子成分：

(1) 定语
We live on the fifth floor. 我们住在五楼。
His father died in the Second World War. 他父亲在第二次世界大战中死去。

(2) 主语
The first is better than the second. 第一个比第二个要好。
The third of the month is my birthday. 这个月的三号是我的生日。

(3) 宾语
She chose the second. 她挑选了第二个。
He was among the first to arrive. 他是首批到达的。

(4) 表语
Jack is always the first to get to the office in the morning. 杰克每天早晨总是第一个来到办公室。
Who was the third? 谁是第三名？