I'm going to see an old schoolmate of mine.
我去见一个老校友。
My father still keeps in touch with his old schoolmate.
我父亲仍和他的老同学保持联系。
He started the magazine with a schoolmate
他和一个同学创办了那份杂志。
On my graduate student's time, an schoolmate's paper discussed this topic.
我上研究生的时候一个同学论文就是做的这个题目。
10 years after graduation, he could hardly recognize his old schoolmate.
毕业10年后，他几乎认不出他以前的同学了。