18 years old
at the age of 18
18-year-old
1,表示多少歲,可以直接用數字:
My elder brother is 18.
我哥哥二十五歲。
2,表示多少歲,可以直接用數字+years+old:
Jane’s mother was 22 years old when she married Jane’s father.
簡的母親嫁給簡的父親時才22歲。
3,表示歲數的時候加連字符“-”,可以做形容詞修飾名詞或直接代替名詞:
The 18-year-old boy was admitted in the university.
這個18歲的男孩被大學錄取了。
This is a birthday party for 10-year-olds.
這是一個10歲的孩子們開的生日聚會。
注意,加連字符“-”,year不能用複數years
That bottle of Maotai is 25 years old.
That bottle of Maotai is 25-year-old.
那瓶茅臺酒已經25年了。