(1) 一般直接用基数词表示,如:

Her daughter is eighteen. 她的女儿18岁。

(2) 用“基数词 years old”表示,有时可将years old 换成years of age。如:

Her daughter is eighteen years old. / Her daughter is eighteen years of age. 她的女儿18岁。

(3) 用“at the age of 基数词”表示。如:

Her daughter got married at the age of eighteen. 她的女儿18岁就结了婚。

(4) 用“基数词-year-old”表示,此结构常做(前置)定语。如:

Her 18-year-old daughter is now in the university. 他18岁的女儿现在上大学。

(5) 用“of 基数词”表示,此结构常做后置定语。如:

Her daughter is now a pretty girl of 18. 她女儿现在一个18岁的美少女了。

(6) 用“aged 基数词”表示,此结构常做后置定语。如:

Lying on the floor was a boy aged about seventeen. 躺在地板上的是一个约莫十七岁的男孩。

(7) 用“be in one’s 几十的复数形式”表示某人大概的年龄。如:

He went to the United States in his fifties. 他五十多岁时去了美国。