Young children are beginning their formal education sometimes as early as four years old.

幼儿有时早在四岁时就开始接受正规教育。

《牛津词典》

When Winston is four years old, the foster family must return it to the training center.

温斯顿四岁的时候，寄养家庭必须把它送回培训中心。

youdao

Jack is only four years old.

杰克只有四岁。

youdao

She was eighty-four years old. She was buried near the remains of her husband in the state of South Carolina.

VOA: special.2010.08.08

I'm sixty-four years old and I haven't had one second of genius in my entire life.

我已经六十四岁了,这辈子都没有哪怕一秒钟灵光乍现的时候

耶鲁公开课 - 聆听音乐课程节选

And a twenty-four-year-old Milton, after seven years of education, simply decides not to go. Instead of joining the ministry, Milton instead returns home and he stays at home without any means of supporting himself for six years.

而24岁的弥尔顿，在结束了7年的学业之后，却决定不那么做,他反而是回到了家中,在家里呆了6年。

耶鲁公开课 - 弥尔顿课程节选

In Europe cars are tested at four-years-old and then every year.

BBC: Isle of Man public consulted on compulsory MOT tests

In the book Rebecca tells him very gently that he too was tested for HIV when he was just four-years-old, and he also has the disease.

BBC: Mothers preparing to die

Four schools -- 10 years old.

WHITEHOUSE: First Lady Previews the 2012 White House Holiday Decorations | The White House