原因状语从句

(1)原因状语从句通常由because, since, as引导。例如:①He didn’t come to school because he was ill.②As it is raining, we shall not (不得;不应该)go the zoo.③Since you can’t answer the question, I’ll ask someone else.(2)because表示直接原因,语气最强。Because引导的原因状语从句多放在主句之后。回答由why提出的问题,只能用because。As和since语气较弱,一般用来表示明显的原因。由as和since引导的原因状语从居多放在句首。例如:①--Why aren’t going there? --Because I don’t want to.②As he has no car, he can’t get there easily.③Since we have no money, we can’t buy it.(3)because和so不能同用在一个句子里。