Dan's class know Dan is in the hall before they see him.

丹的同学还没见到他，就知道他在大厅里了。

youdao

Before class starts or at home, if you know what the lecture is on, try to read the chapter before class starts.

在课程开始之前或者是在家里，如果你知道这个课要讲什么，试着在课程开始之前看看这章的内容。

youdao

Be sure to let your instructor know about any orthopedic problems or special needs you may have before the class begins.

确信你的教练知道你的整体状况，或是一些特殊需要。

youdao

In a report that is as partisan as it is breathless, a group of GOP lawmakers who call themselves the Repeal CLASS Working Group (at least you know where they stand) pretend they have found shocking evidence that the Obama Administration knew CLASS would fail before it included the idea in the health reform law.

FORBES: The Phony CLASS Act Scandal