我刚才在封面上发现了一处错误。

I've just spotted a mistake on the front cover.

《牛津词典》

在老师评讲试卷的时候，我竟然发现试卷上还有一处错误。

When the teacher commented paper, I found that there is a mistake on the paper.

youdao

在老师评讲试卷的时候，我竟然发现试卷上还有一处错误。

When the teacher commented paper, I found that there is a mistake on the paper.

youdao