as ,for,since,because的区别

题目

as ,for,since,because的区别

答案

as,because,since,for用法区别
前三者引导原因状语从句,for引导的则为并列句.
as表示明显原因,语气较because强,例如：
As it is raining,we’ll stay (at) home.
because表示内在的、必然的因果关系,语气较强,例如：
He has to leave because it is too late.
since表示鉴于某种既定事实而为之,语气较弱,例如：
Since everyone is here,we can begin our lesson.
for只是作为补充说明,不用于某种结果之前,表示判断某种情况的因素,语气较because弱,但较为郑重、正式,不能放在句首,例如：
I’ll stay home,for I must wait for a friend.