Run through your notes before class.

上课前把笔记复习一下。

I have to bat out a term paper before class.

我必须在上课前匆匆写出一篇学期论文。

John is playing with Harry before class.

上课前约翰正在和哈利玩。

He told us a story full of humor before class.

他在上课前给我们讲了个非常幽默的故事。

We could chat about the topic before class.

我们上课前就此话题聊天。