序数词的用法（序数词的基本用法）

二分之一 one second=a half

He was second in the exam.

起初 at first

They have two children, and next year they will have a third child.

序数词的用法在初中阶段很重要，也是考试中的高频考点，现将其用法汇总如下：

two and three fourths

5月5日

三分之一 one third

Li Lei&39;s second book is old.

写作：May 5, May 5th, May the fifth, 5 May, 5th May

首先 first of all

部分分数可以使用 half 和 quarter。

The first student to come to school is usually Jim.

带分数: 整数+分数

He is my first English teacher.

母序子基 : 即分母用序数词，分子为基数词，分子大于1，分母加－s.

The long river is the second longest river in China.

四分之一 one fourth=a quarter

四分之三 three fourths =three quarters

He ran the third fastest in his class.

读作：May (the) fifth, the fifth of May

三分之二 two thirds

序数词前也可以使用a或an, 表示的含义是“又一，再一”，常常有语言环境；

第一次 for the first time