since的用法
since如何正確使用呢?以下是小編帶來的since的用法，希望對你有幫助。
一.Since作為介詞，后接某一確定的時間點，主句謂語動詞是持續性動詞，常與現在完成時態、現在完成進行時態或過去完成時態連用。例如：
1、He left the village in 1982 and I haven’t seen him since then.1982年他離開這個村子，從那以后我再沒見過他。
2、She’s been working in a bank since leaving school.她中學畢業后就一直在一家銀行工作。
3.He had spoken to her only once since the party. 自從那次聚會以來，他只跟她說過一次話。
二.Since作為副詞，表示從過去以來、以后或到現在的情形或狀態，常與現在完成時態連用。例如：
1.He left home two weeks ago and we haven’t heard from him since. 他兩周前離開了家，到現在我們一直沒有他的消息。
2.He came to Zhenjiang 6 years ago and has lived here (ever) since.他6年前來到鎮江，從此便住在這里。
三.since引導原因狀語從句
作為連詞，since可引導原因狀語從句，表示因為;既然;鑒于：例如：
1. He didn’t come since he was busy.他因為忙，所以沒有來。
2. Since this method doesn’t work,let’s try anoter.既然這種方法不行，我們就試用另一種吧。
四.Since引導時間狀語從句
1.若since引導的狀語從句的謂語是終止性動詞的過去時，則從句表示的時間是“從動作開始的那一時刻起”。例如：
He has studied very hard since he came to our school.自從他來到我們學校，他學習就非常努力。
We have been missing them since they left here自從他們離開這里，我們就一直很想念他們。
2.若since引導的.狀語從句的謂語動詞是持續性動詞或表示狀態動詞的過去時時，則從句表示的時間是“從動作或狀態結束時算起”。例如：
I haven’t heard any noise since I slept. Sleep 為持續性動詞，sleep的動作結束時，即“醒來”時，所以這句應譯為“我醒后還未聽到任何聲音”。
3.若since引導的狀語從句的謂語為持續性動詞的現在完成時，則表示動作和狀態延續到現在(說話時刻)，其表示的時間的起點應從動作發生之時算起。例如：I haven’t heard from him since he has lived there。 這里has lived表示動作的持續性，時間的起點應從：“開始居住”時算起。因此此句可理解為“自從他(開始)住在那兒起，我就一直沒收到他的來信”。
五.Since在特殊句型中的應用
句型I：“It is (has been)+時間+since+持續性動詞的過去時”，表示“自從……以來到現在已有多久。”例如：
It has been quite some time since I was last in London.我上次離開倫敦至今頗有一段時間了。
句型II：“It was+時間+since+持續性動詞的過去完成時”,表示“從……到過去某時間點以來”，例如：It was three years since we had been here.那時我們在這已呆了三年。
六.鞏固練習
(一)單項選擇
1.—Do you smoke?
—_____ .It's two years since I smoked.
A.Yes，I do B.No，I don't C.Not too much D.Oh，but I wish I didn't
2.Since you are busy, you __________ tomorrow.
A. don’t need come B.need not come C. needn’t come D.mustn’t come
3.---Has he been home?
---______,he _________home since he graduated.
A. No; hasn't been B.Yes;has been C.No; isn’t D.Yes; is
4.They _________friends since they met in Shanghai.
A.haven’t been B.have been C. aren’t D. are
5.I_______here since he left the door open,but it seems that he won’t come back today.
A. have been waiting B.will have waited C.was waiting D.waited
6.I _________ from him since he has lived here.
A. heard B. have heard C. have never heard D.have been hearing
7. He came to China _______ 1998.
A. from B. since C. at D. in
8.-- Excuse me.Did you notice whether the No.18 bus had gone by?
--Not __ _ I began to stand here.
A.as B.when C.since D.while
(二)漢譯英：
1.他好久沒學英語了。
2. 自從我生病以來，他從未來看過我。
3. 自從我病愈以來，他從未來看過我。
4. 約翰現在和父母一起住在紐約，他不當教師已經三年了。
5.自從我們看望你母親以來到現在有多長時間了?
參考答案(一)：
1.B 。“It is (has been)+時間+since+持續性動詞的過去時”，表示“已有多久沒……了”。 It's two years since I smoked.意思是“我兩年沒有抽煙了，故選擇B項。
2、C。不必做某事：needn’t do sth.，所以選擇C項。
3、A。“since引導的時間狀語從句的謂語是終止性動詞的過去時，則從句的時間是“從動作開始的那一時刻算起”。 “he hasn't been home since he graduated”表示“自從他畢業以來，他就離開了家”，故選擇A項。
4、B。用法同練習3。“They .have been friends since they met in Shanghai”，自從他們在上海相識以來，一直是朋友。故選擇B項。
5.A 。I have been waiting here since he left the door open,but it seems that he won’t come back today意思是“自從他關上門以來，我一直在等他，但他是乎今天回不來了”。故選擇A項。
6.C。since引導的時間狀語從句的謂語為持續性動詞的現在完成時，則表示動作和狀態延續到現在(說話時刻)，其表示的時間的起點應從動作發生之時算起。“I have never heard from him since he has lived there ”意思是“自從他(開始)住在那兒起，我從未收到他的來信”。故選擇C項。
7.D。表示時間點用in，句子時態是過去時，故選擇D項。
8.C。用法同練習3。 “Not since I began to stand here”意思是“自從我開始站在這里就沒有注意到”。故選擇C項。
(二)
1. It’s a long time since he studied English.
2. He has never been to see me since I have been ill.
3. He has never been to see me since I was ill.
4. John is now with his parents in New York, it is already three years since he was a teacher .
5. How long is it since we visited your mother?
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