while前面和后面的时态

　　while的具体用法

　　1、“当……时候”，引导时间状语从句(从句动作必须是延续性的)。

　　Please don't talk so loud while others are working.

　　While I was cleaning the window，my finger was seriously cut。

　　2、“虽然，尽管”相当于although，引导让步状语从句(常把while放在句首)。

　　While she is a top student， she has some shortcomings. While the Internet is bridging the distance between people， it may also be breaking some home or will cause other family problems。

　　3、“只要，如果”等于as long as，引导条件状语从句。

　　There is hope while there is life. While you study hard， your effort will pay off。