triennial

Occurring every third year.

每三年的每三年出现一次的，三年一次的

occurring every third year or lasting 3 years.

每三年发生一次的，或持续三年的。

He served in the army for three years.

他服了三年的兵役。

Work of the Past Five Years and Basic Experience of 13 Years

过去五年的工作和十三年的基本经验

Three years ago, my ideal--"

三年前我的理想——”

The third and fourth grades are in this three-story building.

三年级和四年级在这栋三层的楼里。

a plant lasting for three seasons or more.

生命力持续三年或三年以上的植物。

The primary grades in school are grades one through three.

学校的低年级是一年级到三年级。

in a short span of three years

在短短的三年时间内

(4) where the registered trademark has ceased to be used for threeconsecutive years.

（４）连续三年停止使用的。

where the registered trademark has ceased to be used for three consecutive years.

连续三年停止使用的。

She has been on the stage for over thirty years.

她有三十多年的艺龄。

rural life in the Thirties.

三十年代的农村生活

over 30 years of experience

三十余年的教学经验

His three-year hitch is not yet completed.

他的三年兵役还没有满。

His money doubled in three years.

他的钱三年增加了一倍。

the(Triple) Entente

(1907年的英、法、俄)三国协约;三个协约国

The third month of the years is March.

一年中的第三个月是三月。