She has been singing professionally for over twenty years.

VOA: special.2009.03.11

Let me say, I've been teaching this course now for over twenty years and I'm very proud of all of my alumni.

那个...,我教这门课已经有20多年的时间了,我为自己的毕业生所骄傲

耶鲁公开课 - 金融市场课程节选

This is how I end the previous course, but it's the most appropriate place to start this one, because the Paris Commune hung over Europe for the next twenty or thirty years.

我上节课结束时就讲到这里,这十分适合作为这节课的开头,因为巴黎公社的阴霾,笼罩了欧洲接下来的二三十年

耶鲁公开课 - 1871年后的法国课程节选