一、作为介词
表示时间
意为 “自从…… 以来”,后接过去的某个时间点,常与现在完成时态连用。例如:“I have lived here since 2010.”(自 2010 年以来我一直住在这里。)
也可以接一个表示过去动作的名词短语,如 “since his graduation”(自从他毕业)。
二、作为连词
引导时间状语从句
从句中的谓语动词通常用一般过去时,而主句用现在完成时。例如:“Since I came to this school, I have made many friends.”(自从我来到这所学校,我已经交了很多朋友。)
若表示 “从过去某一时间开始一直持续到过去另一时间”,则主句用过去完成时,从句用一般过去时。例如:“He had worked in the factory since he moved to the city until he got married.”(从他搬到这座城市直到他结婚,他一直在这家工厂工作。)
引导原因状语从句
相当于 “because”,表示 “因为;既然;鉴于”,但语气较弱。例如:“Since you are free today, you can help me with my housework.”(既然你今天有空,你可以帮我做家务。)
三、作为副词
意为 “从那时以后;后来;此后”,常与完成时态连用。例如:“He left home in 1990 and has not been heard of since.”(他在 1990 年离家,此后便杳无音信。)
We've lived here since 1994.
自1994年以来我们一直住在这里。
I haven't eaten since breakfast.
早饭以后我还没吃过东西呢。
He's been working in a bank since leaving school.
他中学毕业以后一直在一家银行工作。
Since the party she had only spoken to him once.
那次聚会以后,她只和他说过一次话。
That was years ago. I've changed jobs since then .
那是多年以前的事了。自那以来我已经换过几个工作了。
Since when did he ever listen to me?
他什么时候听过我的话?