1.原因状语从句指在句中用来说明主句原因的从句。
2.引导原因状语从句的从属连词有because(因为),as(由于),since(既然), now(that)(既然), when(既然), seeing (that) (由于,鉴于), considering (that)(考虑到), for(为), given (that)(考虑到)等。