引导原因状语从句的连词：
because: Because it rained he took a taxi. 由于下雨他叫了一辆出租车。
as: As youre sorry, Ill forgive you. 既然你悔悟了，我就原谅你。
Since: Since you will go there, I will go too.
让步状语从句的连词：although / though:Though / Although it is not large, the room was light . 房间虽然不大，采光却很好。
even if: Theyll stand by you even if you dont succeed. 即使你不成功，他们也会支持你。