since

prep.

1. 自…以后；从…以来
   from a time in the past until a later past time, or until now
   1. She's been off work since Tuesday.
      星期二以来她一直没上班。
   2. We've lived here since 1994.
      自1994年以来我们一直住在这里。
   3. I haven't eaten since breakfast.
      早饭以后我还没吃过东西呢。
   4. 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。
   5. 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。
   6. ‘They've split up.’ ‘ Since when? ’
      “他们分手了。”“什么时候的事儿？”
   7. 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。
2. （表示气愤）何曾，什么时候
   used when you are showing that you are angry about sth
   1. Since when did he ever listen to me?
      他什么时候听过我的话？

conj.

1. 从…以后；自…以来
   from an event in the past until a later past event, or until now
   1. Cath hasn't phoned since she went to Berlin.
      卡思自从去了柏林还没有打来过电话。
   2. It was the first time I'd had visitors since I'd moved to London.
      那是我搬到伦敦以后第一次有人来看我。
   3. It's twenty years since I've seen her.
      我已经二十年没见她了。
   4. How long is it since we last went to the theatre?
      我们多久没去看戏了？
   5. She had been worrying ever since the letter arrived.
      自从接到那封信后她就一直焦虑不安。
2. 因为；由于；既然
   because; as
   1. We thought that, since we were in the area, we'd stop by and see them.
      我们想，既然到了这个地方，就该顺便去看看他们。

adv.

1. 自…以后；从…以来
   from a time in the past until a later past time, or until now
   1. He left home two weeks ago and we haven't heard from him since.
      他两周前离家外出，我们至今还没有他的音信。
   2. The original building has long since (= long before now) been demolished.
      原来的建筑老早就拆了。
2. 此后；后来
   at a time after a particular time in the past
   1. We were divorced two years ago and she has since remarried.
      我们两年前离了婚，之后她又再婚了。

1. PREP (表示某情况自过去某时间点或某个事件以来一直持续到现在)自…以后，从…以来
   You use since when you are mentioning a time or event in the past and indicating that a situation has continued from then until now.
   1. Jacques Arnold has been a member of parliament since 1987...
      雅克·阿诺德自 1987 年以来一直是议会议员。
   2. She had a sort of breakdown some years ago, and since then she has been very shy...
      几年前她得了神经衰弱，自那以后就变得十分腼腆。
   3. I've been here since the end of June.
      自6月末以来我就一直呆在这儿。
   4. Since is also an adverb.
      
   5. When we first met, we had a row, and we have rowed frequently ever since...
      我们第一次见面时就吵了一架，此后经常吵。
   6. They went to Dartmouth College together in the 1960s and have frequently done business together since...
      20 世纪 60 年代时他们一起去达特茅斯学院求学，之后也经常合伙做生意。
   7. I returned home to Sussex and have since worked as a solicitor.
      我回到了家乡萨塞克斯郡，之后就一直做事务律师。
   8. Since is also a conjunction.
      
   9. I've earned my own living since I was seven, doing all kinds of jobs.
      从 7 岁起我就自己养活自己，做过各种工作。
   10. ...the problems the movie company had had ever since it set up camp on Sketon Island.
       自从该电影公司在斯凯顿岛建立营地后所面临的种种问题
2. PREP (表示某事件或情况从过去某时间或某个事件之后一直发生)自…以来,在…之后
   You use since to mention a time or event in the past when you are describing an event or situation that has happened after that time.
   1. The percentage increase in reported crime in England and Wales this year is the highest since the war...
      今年英格兰和威尔士报道的犯罪增长率是战后以来最高的。
   2. He turned out to have more battles with the Congress than any president since Andrew Johnson.
      结果他是自安德鲁·约翰逊以来和国会斗争最多的一任总统。
   3. Since is also a conjunction.
      
   4. So much has changed in the sport since I was a teenager...
      自打我十几岁以来，这项运动已经有了很大改变。
   5. Since I have become a mother, the sound of children's voices has lost its charm.
      自打我做了母亲后，孩子们的声音就不那么动听了。
   6. ...a slight accent she had acquired since he last saw her.
      自他最后一次见到她之后，她就有了轻微的口音
3. ADV (表示过去某事或某情况发生后不久又发生了另一件事)此后，后来
   When you are talking about an event or situation in the past, you use since to indicate that another event happened at some point later in time.
   1. About six thousand people were arrested, several hundred of whom have since been released...
      约 6,000 人被捕，后来其中的几百人又被释放了。
   2. His style of leadership has attracted increasing criticism among his supporters, many of whom have since left Central Office.
      他的领导风格已经在他的拥趸中引起了越来越多的批评，很多人后来离开了总局。
4. PHRASE 早就
   If you say that something has long since happened, you mean that it happened a long time ago.
   1. Even though her parents have long since died, she still talks about them in the present tense.
      尽管双亲早已离世，她谈论起他们时好像他们至今健在。
5. CONJ-SUBORD 因为;由于;既然
   You use since to introduce reasons or explanations.
   1. I'm forever on a diet, since I put on weight easily...
      我永远都在减肥，因为我很容易长胖。
   2. Since she did not make enough money to live in her own house, she went back to live with her mother.
      她挣的钱不够自己一个人住，于是搬回去和她妈妈一起住了。

Do not confuse for and since. You use for to say how long a period lasts in the past, present, or future, or how much time passes without something happening. She slept for eight hours... He will be away for three weeks... I hadn't seen him for four years. You use since to say when a period of time started. She has been with the group since it began. ...the first civilian president since the coup 17 years ago. You also use since to refer to the last time that something happened, or to how much time passes without something happening. She hadn't eaten since breakfast... It was a long time since she had been to church. You can use because, as, since, or for to give an explanation for something. Because is the commonest of these, and is used when answering a question beginning with 'why?'.You can use as or since instead of because to introduce a clause containing a reason for something, especially in writing. ...a note about The National Portrait Gallery, as the word 'Gallery' can be misleading... Since the juice is quite strong, you should always dilute it. In stories, for is sometimes used to explain or justify something. He seemed to be in need of company, for he suddenly went back into the house. Note that because is a conjunction, and is used to link two ideas within one sentence. I'm unsocial, because of my deafness.
不要混淆 for 和 since。for 用来表示过去、现在或将来的一段时间，还可表示某段时间内某事没有发生：She slept for eight hours (她睡了 8 小时)，He will be away for three weeks (他将离开 3 周)，I hadn't seen him for four years (我有 4 年没见他了)。since 用来表示某段时间的起点：She has been with the group since it began (该集团创建之初她就在那儿工作)，the first civilian president since the coup 17 years ago (17 年前政变后的第一个平民总统)。since 还可用来指某事发生的最后时间，或某段时间内某事没有发生：She hadn't eaten since breakfast (早饭后她一直没吃过东西)，It was a long time since she had been to church (她很久没去教堂了)。because，as，since，for 均可用来解释原因。because 最常用，用来回答以 why 开头的疑问句。 as 或 since 可用来代替 because 引导一个表示原因的从句，尤用于书面语：a note about The National Portrait Gallery, as the word ‘Gallery’ can be misleading (对 The National Portait Gallery 的注释，因为 Gallery 一词容易令人误解)，Since the juice is quite stong, you should always dilute it (由于果汁很浓，你必须加水稀释)。在讲述故事时，for 用来对某事作出解释或论证：He seemed to be in need of company, for he suddenly went back into the house (他似乎需要人作伴，因为他突然返回了房子里)。注意，because 是连词，用于连接一个句子中的两个意思：I'm unsocial, because of my deafness (我不善交际, 因为我耳朵聋)。

1. My grandson has been away since last October.
   我的孙子自去年10月份就离开了。
2. Prices have climbed by 21% since the beginning of the year
   年初以来，物价已经上涨了21%。
3. How many years is it since we've seen each other? Too many, anyway.
   我们多少年没有见面了？反正有年头了。
4. Eight new national newspapers have appeared on the newsstands since 1981.
   自1981年以来，8种新的全国性报纸出现在报摊上。
5. It's been 200 years since the passage of the Bill of Rights.
   《人权法案》通过已经200年了。
6. Since when have you been interested in poetry?
   你从什么时候开始对诗歌感兴趣的？
7. The ideas were not new. Their development had proceeded steadily since the war
   这些并不是什么新思想，自从战争开始就一直稳定地发展演变。
8. It was some weeks now since they had had any respite from shellfire.
   他们已经好几周没有在炮火中获得任何喘息的机会了。
9. The period since the revolution has been one of political turmoil.
   革命爆发后就陷入了政治动乱期。
10. He was happily married to a girl he had known since his schooldays.
    他与一个学生时代就认识的女孩幸福地结婚了。
11. Since I separated from my husband I have gone a long way.
    自从我和我丈夫分开后，我的生活发生了很大的变化。
12. Jacques Arnold has been a member of parliament since 1987
    雅克·阿诺德自1987年以来一直是议会议员。
13. She had a sort of breakdown some years ago, and since then she has been very shy
    几年前她得了神经衰弱，自那以后就变得十分腼腆。
14. The percentage increase in reported crime in England and Wales this year is the highest since the war
    今年英格兰和威尔士报道的犯罪增长率是战后以来最高的。
15. He turned out to have more battles with the Congress than any president since Andrew Johnson.
    结果他是自安德鲁·约翰逊以来和国会斗争最多的一任总统。
16. About six thousand people were arrested, several hundred of whom have since been released
    约6,000人被捕，后来其中的几百人又被释放了。
17. His style of leadership has attracted increasing criticism among his supporters, many of whom have since left Central Office.
    他的领导风格已经在他的拥趸中引起了越来越多的批评，很多人后来离开了总局。
18. Even though her parents have long since died, she still talks about them in the present tense.
    尽管双亲早已离世，她谈论起他们时好像他们至今健在。
19. I'm forever on a diet, since I put on weight easily
    我永远都在减肥，因为我很容易长胖。
20. Since she did not make enough money to live in her own house, she went back to live with her mother.
    她挣的钱不够自己一个人住，于是搬回去和她妈妈一起住了。
21. It had been two years since I had been to the swimming baths.
    我已经有两年没去过室内游泳馆了。
22. He had long since written off the money.
    他很早就将那笔钱勾销了。
23. It's only a year since I last saw the child and he's grown so tall.
    这孩子一年不见，长这么高了。
24. It is nearly two years since I came here.
    我来这儿快两年了。
25. I have long since come to terms with my blindness.
    我早就安于自己的失明了。
26. Two weeks has passed since the new term began.
    开学以来两个星期已经过去了。

  after since【导航词义：在…之后】

  after prep., conj. （时间）在…以后

〔辨析〕一般不与现在时间发生关系，故常和动词的过去时或过去完成时连用。

  since prep., conj. 自…以来

〔辨析〕

  because as for since【导航词义：因为，由于】

  because conj. 因为

〔辨析〕语气最强，表示因果关系，通常用来回答由 why 引导的疑问句。由 because 引导的分句置于句首时，须用逗号与主句隔开，置于句末时则不用隔开。

  as conj. 因为，由于

〔辨析〕如果所述理由是明显的或者已知的，则用 as 较 because 更为合适。

  for conj. 〈正式〉因为

〔辨析〕for 属于并列连词，由它引导的分句表示补充说明性的理由，通常只能置于句末，且必须用逗号与前面的分句隔开。

  since conj. 因为，既然

〔辨析〕当所述原因是已知的客观事实或被当作推断的理由时用 since，语气略强于 as。