他去年在他的年龄段排名第二。

Last year, he was ranked second in his age group.

《牛津词典》

问题出在他的年龄。

The problem is his age.

youdao

在他的年龄，如果你打不上比赛，你很难保持在你的最佳状态上。

At that age, it is very difficult to stay at your best if you do not play.

youdao

And his discoveries that-- they did them in different ways at different ages led to the emergence of the Stage Theory.

他发现,儿童在不同的年龄拥有不同的行为方式,他根据这一发现提出了阶段理论

耶鲁公开课 - 心理学导论课程节选