because名词形式

because是连词，没有名词形式，例如：

1、They are here because of us.他们是因为我们来这里的。

2、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。

3、His school work is suffering because of family problems.由于家庭问题，他的学业日渐退步。