because加逗号规则

because引导的原因状语从句一般放于主句的后面，because从句位于句首时要用逗号分开，放在句末时，可不用逗号分开。because表示直接原因，语气最强，最适合回答why引导的疑问句。

We couldn\'t understand them because they were talking in Chinese.

我们听不懂他们在讲些什么，因为他们说的.是汉语。

His school work is suffering because of family problems.

由于家庭问题，他的学业日渐退步。

Two players are out of the team because of injury.

两名队员因伤退出了比赛。