I'm going to call on one of my former classmates.

我要去看望我的一位老同学。

《新英汉大辞典》

When I was in my university, one of my classmates sat beside me.

当我在我的大学里时，我的一个同学坐在我旁边。

youdao

One of her classmates, the one with two mommies, showed up to school every single day dressed in a Cinderella gown, with a bridal veil.

她的同班同学，一个有两个妈妈的小女孩，每天上学都穿着一套灰姑娘的礼服裙，还带着新娘面纱。

youdao

In Paris, Isabella became close friends with one of her classmates, Julia Gardner, whose family was from Boston, Massachusetts.

VOA: special.2009.01.11

So I thought I'd begin with a short note that one of your classmates sent to me earlier this week.

我从这周早些时候,你们其中一个同学给我的一张字条开始。

哈佛公开课 - 计算机科学课程节选

Let's say that one of your classmates puts make up on all the time.

假设你有一个同学总是带妆出门。

remind me of 课堂 - SpeakingMax英语口语达人

She did a great job, great job. (Applause.) Just know that we're all very proud of you, and we're all very proud of every single one of your classmates and every single student here in the city of Philadelphia and the state of Pennsylvania.

WHITEHOUSE: Making Healthy Food Accessible & Affordable

One student said she learned one of her classmates was stabbed after leaving the school's Health Science Center building.

NPR: Student Arrested In Texas College Stabbing Attack

It all hit home one weekend this spring when I took Neva to a birthday party for one of her classmates.

WSJ: Being a Murphy Brown Working Mom in a June Cleaver Stay-at-Home World