我一下课就马上去图书馆。

I'm going to the library straight after the class.

《牛津词典》

一下课，我就冲向车站。

As soon as the class was over, I made a dash for the bus station.

youdao

他一下课就洗了手。

Right after class, he washed his hands.

youdao

I do try to start a few minutes late, but I also have to finish a few minutes early so you can go to your next class.

我已经推迟上课好几分钟了,我还得提前下课,好让你们能赶上下一节课

耶鲁公开课 - 基础物理课程节选

Now before you guys go, there's one more thing I wanted to mention, and then I'll show today's comedy clip which is a good one by the way-- they're all good, but this one's especially good.

下课之前,还有一件事情我要说一下,说完就给你们放今天的动画短片,很不错的,所有动画短片都不错,不过这个尤其好

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选