Since用法

Since一、用作介词，意思是“从……以来，自从”，常与完成时连用。

I haven’t written home since Christmas. 自圣诞节以来，我未曾写信回家。

二、用作副词，意思是“从那时以后(一直到现在)”，“其后(到现在之间)”;ever since从那以后一直(更加强调since的用法)。

Things have not changed very much since.His first book was a great success and he has been famous as a writer ever since.He got a job with the firm in 1970 and has worked there ever since.三、用作连词1. 引导原因状语从句，相当于now that，意思是“因为……，既然……，鉴于……”。

Since the rain has stopped，let’s go for a walk. 既然雨停了，我们出去散散步吧。

Since we are young，we shouldn’t be too afraid of making mistakes.因为我们还年轻，所以不应该太害怕犯错误。

注意：since表示原因时，语气比because弱，表示的原因是对方已知的，或是句中不很重要的部分，是附带的原因，因此引导的从句不是信息的焦点，不能回答why的提问，也不能用在强调句型中作为被强调的内容。

since引导的从句往往放在主句之前。

2. 引导时间状语从句，此用法较复杂。

(1) 若since引导的状语从句的谓语动词是终止性动词(如go，come，leave，start，begin 等)的过去时，则从句表示的时间是“从该动作开始的那一时刻起”。

这是最常见的一种用法。

如：He has studied very hard since he came to our school. 自从来到我们学校，他学习就非常努力。

Great changes have taken place in our school since you left.(2) 若since引导的状语从句的谓语动词是持续性动词或表示状态的静态动词(如live，stay，study，learn，smoke，be等)的过去时，则从句表示的时间是“从该动作或状态的完成或结束时算起(否定)”。

如：I haven’t heard from him since he lived here. 从他不住这儿起，我一直没有收到他的信。

I haven’t eaten snakes since I was a student at school. was表示状态，因此该句可理解为：I haven’t eaten snakes since I left school. 自从我毕业后就一直没吃过蛇。

He has written to me frequently since I was ill. 自从我病愈以来，他经常给我写信。

He has written to me frequently since I fell ill. 自从我生病以来，他经常给我写信。

(从句谓语为终止性动词)(3) 若since引导的状语从句的谓语为持续性动词或静态动词的现在完成时，则表示动作和状态延续到现在(说话时刻，肯定)，其表示的时间的起点应从动作发生之时算起。

如：He has written to me frequently since I have been ill. “自从我生病以来，他经常给我写信。

”I’ve written her 20 letters since I have been here. 自从我来到这，我已经给她写了20封信。

I’ve written her 20 letters since I was here. 自从我离开这儿，我已经给她写了20封信。

(4) It is + 段时间+ since... / It has been + 段时间+ since...表示“从……起已有多长时间了”。

两句型意思相同，前者是规范说法，后者是口语说法。

用法：since从句中常用一般过去时，若从句中是持续性动词的一般过去时，则表否定。

It is three years since he smoked. 他不吸烟已有3年了。

It is three years since he began to smoke.It is three years since he has smoked. 两句均意为：他吸烟已有3年了。

注意：在这种结构中，since引导的从句绝对不能用否定式的谓语动词来表示否定意义.他好久没学汉语了。

误：It is a long time since be didn’t study Chinese.正：It’s a long time since he studied Chinese. (studied为持续性动词，应从其动作结束时算起)since的用法主要有两点：一是表示“自从……以来”，二是表示“既然”之意。

但如果只了解词的含义，而不了解其用法，在使用时就会造成错误。

例如：I have not heard from him since I lived in Shanghai.不少人会望文生义，将该句译为：“自从我住在上海以来，就再也没有收到他的信了。

”而实际上这个句子的译文并非如此。

下面谈谈since作连词引导时间状语从句的用法。

一、若since引导的状语从句的谓语动词是终止性的过去时，则从句表示的时间是“从动作开始的那一时刻起”。

如：He has studied very hard since he came to our school.从他来到我们学校，他学习就非常努力。

We have been missing them since they left here自从他们离开这里，我们就一直很想念他们。

二、若since引导的状语从句的谓语动词是持续性动词或表示状态的动词的过去时时，则从句表示的时间是“从那持续动作或状态结束时算起”。

如： I haven’t heard any noise since I slept.Sleep 为持续性动词，sleep的动作结束时，即“醒来”时，这句应译为“我醒后还未听到任何声音”。

John is now with his parents in New York, it is already three years since he was a teacher约翰现在和父母一起住在纽约，他不当教师已经三年了。

How long is it since you lived in Shanghai?你离开（没住在）上海多久了？It is half a month since he was a League member.他退团（不当团员）半个月了。

It’s been quite some time since I was last in London我离开伦敦已很长时间了。

He has written to me frequently since I was ill.自从我病愈以来，他屡次给我写信。

（从句谓语为状态动词）He has written to me frequently since I fell ill.自从我生病以来，他就屡次给我写信。

（从句谓语为终止性动词）三、若since引导的状语从句的谓语为持续性动词的现在完成时，则表示动作和状态延续到现在（说话时刻），其表示的时间的起点应从动作发生之时算起。

如： I haven’t heard from him since he has lived there。

这里has lived表示动作的持续性，时间的起点应从：“开始居住”时算起。

因此此句可理解为“自从他（开始）住在那儿起，我就一直没收到他的来信”。

Since we have owned a car, we have gone camping every year。

自从我们自己有了汽车，我们每年都去野营。

Since I’ve been at this school, we have had three headmasters.自从我到这所学校，我们已换了三个校长了。

Since I was at this school, they have had three headmasters.自从我离开这所学校，他们已换了三个校长了。

2.He has never been to see me since I have been ill. 自从我生病以来，他从未来看过我。

He has never been to see me since I was ill. 自从我病愈以来，他从未来看过我。

由此可见，since引导的从句持续动词的一般过去时和现在完成时所表示的意思恰好相反。

换言之，一般过去时持续动词以肯定的语法形式反映着否定的逻辑内容，而现在完成时的形式与内容是一致的。

至于It is +一段时间+since…的句型与It has been +一段时间+since…意思相同。

前者是规范说法，后者是口语说法。

应注意的是，在这种结构中，since引导的从句绝对不能用否定式的谓语动词来表示否定意义，下面两句都错了：It is a long time since he didn’t study English. It’s two months since you didn’t come to see me. 正确的说法为：It’s a long time since he studied English 他好久没学英语了。

You haven’t come to see me for two months. 你有两个月没来看我了。

1)since +过去一个时间点(如具体的年、月、日期、钟点、1980, last month, half past six)。

I have been here since 1989.2) since +一段时间+ ago I have been here since five months ago.3) since +从句Great changes have taken place since you left.Considerable time has elapsed since we have been here.4) It is +一段时间+ since从句It is two years since I became a postgraduate student.。