In those days most people left school when they were only fifteen years old.

那时候，大多数人上学只上到十五岁。

《牛津词典》

When I was fifteen years old, I became very interested in shopping.

我十五岁的时候，变得对购物非常感兴趣。

youdao

Bet and Nan were fifteen years old—twins.

白特和南恩都是15岁——是双胞胎。

youdao

Ella's mother died when Ella was fifteen years old.

VOA: special.2010.07.04

Alice is fifteen years old at the time, not an entirely unreasonable age for an actress or an amateur actress playing the maidenly but strong-headed Lady of Milton's mask.

当时爱丽丝，15岁，她的年龄完全不适合演弥尔顿所描绘的,沉稳而意志坚强的小姐。

耶鲁公开课 - 弥尔顿课程节选

Juliette has completed a prison sentence of fifteen years for committing the unimaginable crime of murdering her six-year-old son.

NEWYORKER: I've Loved You So Long

In 2003, a seventy-two-year-old patient at the Veterans Hospital in Bedford, Massachusetts, died, fifteen years after receiving a diagnosis of dementia.

NEWYORKER: Offensive Play