He was 14 years old when it happened.(這件事情發生的時候，他14歲。)

Fossil hunters have unearthed the bones of an elephant believed to be 500,000 years old.(化石尋找者們挖掘出了一頭被認為有50萬年之久的大象遺骨。)

I'm fourteen years old.(我14歲。)

Children don't complete their set of 20 baby teeth until they are two to three years old.(孩子到兩三歲時才長齊20顆乳牙。)

I'll be 26 years old next Friday.(我下周五就26歲了。)

When my own son was five years old, I became eager for another baby.(當我兒子５歲的時候，我開始渴望要另一個寶寶。)

I was twenty years old and ready for anything.(我當時二十歲，什么都愿意去做。)

The dirty-faced waif was only five or six years old.(這個流浪兒臉上臟兮兮的，只有五六歲大。)

He was barely 20 years old and already running his own company.(他只有20歲，卻已經營起自己的公司了。)

Young children are beginning their formal education sometimes as early as four years old.(幼兒有時早在四歲時就開始接受正規教育。)