“我会做的。”最年长的儿子说道，他今年21岁，是一名大学生，住在家里。

"I'll do it," says the eldest child, a 21-year-old college student who lives at home.

youdao

最年长的孩子是唯一受到过父母全部精力来关注的孩子。

Eldest children are the only ones to have experienced the undivided attention of their parents.

《柯林斯英汉双解大词典》

你是最年长的女孩，而且没有工作，所以你的工作是帮助我。

You are the oldest girl not working, so it is your job to help me.

youdao

We've always been looking for the oldest Confederate widow, in case you haven't noticed.

我们一直在寻找现存最年长的南部邦联寡妇,要是你注意过这方面消息的话

耶鲁公开课 - 美国内战与重建课程节选

Typically, the youngest guys are twenty, and typically the oldest guys are 45, but everybody was liable to military service in these states until they were about 60.

一般来说,最年轻的二十岁,最年长的四十五岁,但是在有些城邦中,六十岁以下的人都能参军

耶鲁公开课 - 古希腊历史简介课程节选