引导原因状语从句的从属连词主要的有because,for,in that,for the reason that;as,seeing (that), seeing as;since;now (that); considering (that)等：
1.引导原因状语从句的连词主要有because, as, since
例句：
Because it was the rain we took a taxi. 由于下雨他叫了一辆出租车.
He was worried because he hadn’t had any letter from her.他很担忧因为他没收到过她一封信.
2.还有一些表示原因的状语从句由seeing（that）,considering(that)或now that等引导
例句：
Please don’t try to back out now that everything has been arranged.现在一切都安排好了,请不要打退堂鼓.
Now you’re here, you may make yourself useful. 你已经来了,不妨帮帮忙.
3.许多用在形容词后的that从句也起原因状语的作用（that 有时可省略）
例句：
She was glad that she had controlled herself. 她很高兴控制住了自己.
I’m disappointed that they cannot come. 他们不能来我很失望
