讲话前，我必须先表示歉意。

I must preface my remarks with an apology.

《牛津词典》

学生在注册前必须先参加摸底考试。

Students are required to take placement tests before registering.

《柯林斯英汉双解大词典》

她在访问前对这座城市的历史先研究了一番。

She had boned up on the city's history before the visit.

《牛津词典》

Well, let's just give a teaser of some of the details before we move on to actual interesting functionality.

在转去介绍,其他更实际有趣的知识前,我先让大家注意一个小细节。

哈佛公开课 - 计算机科学课程节选

I mean there are definitely other ways around that and by justifying, no, hang on, hang on, before you laugh at me.

我是说，一定有其他变通的办法,通过判定。。。，不对不对，等等，趁没嘲笑我前我先改正。

耶鲁公开课 - 公正课程节选

Maybe somebody who knows Citizen Kane and would like to have a grade for the first 50 pages.

也许比较清楚了解的同学可以做,需要先读前50页的内容。

麻省理工公开课 - 电影哲学课程节选