whenwhile_as,since_的区别用法及练习题.docx

when,while,as,since的用法大总结以及练习题
一.Since作为介词，后接某一确定的时间点，主句谓语动词是持续性动词，常与现在完成时态、现在完成进行时态或过去完成时态连用。

例如：亠
1、He left the village in 1982 and I haven't seen him since then. 1982 年他离开这个村子, 从那以后我再没见过他。

2^ She's been working in a bank since leaving school.她中学毕业后就一直在一家银行工作。

3.He had spoken to her only once since the party.自从那次聚会以来，他只跟她说过一次话。

二.Since作为副词，表示从过去以来、以后或到现在的情形或状态，常与现在完成时态连用。

例如：
1.He left home two weeks ago and we haven't heard from him since.他两周前离开了家，到现在我们一直没有他的消息。

2.He came to Zhenjiang 6 years ago and has lived here (ever) since.他6 年前来到镇江, 从此便住在这里。

三.since引导原因状语从句
作为连词，since可引导原因状语从句，表示因为；既然；鉴于：例如：
1.He didn't come since he was busy.他因为忙，所以没有来。

2.Since this method doesn't work,lei's try anoter.既然这种方法不行，我们就试用另一种吧。

四.Since在特殊句型中的应用
句型I：“It is (has been) +时间+since+持续性动词的过去时”,表示“自从 ...... 以来到现在已有多久。

”例如：
It has been quite some time since I was last in London.我上次离开伦敦至今颇有一段吋间了。

句型II：Tt \vas+时间+since+持续性动词的过去完成时”，表示"从 ... 到过去某时间点以来”，例如：It was three years since we had been here.那时我们在这已呆了三年。

六.巩固练习
(一)单项选择
1.—Do you smoke?
一____ . 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
5.1____ 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
6.1_______ 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?
-I don*t know_ I began to stand here just now・
A.as
B.when
C.since
D.while
现在完成进行时和现在完成时练习
1 ・一Pm sure Andrew will win the first prize in the final.
一I think so. He _______ for it for months. （2008 江苏）
A. is preparing B・ was preparing
C. had been preparing
D. has been preparing
2.By the time he realizes he ________ into a trap, it'll be too late for him to do any thing about it. （2008山东）
A. walks
B. walked
C. has walked
D. had walked
3.So far this year we ______ a fall in house prices by between 5 and 10 percent. （2008 福建）
A. saw
B. see
C. had seen
D. have seen
4.Cathy is taking notes of the grammatical rules in class at Sunshine School, where she _______ English for a year. （2007 湖南）
A. studies
B. studied
C. is studying
D. has been studying
5.Danny ________ hard for long to realize his dream and now he is popular. （2007 福建）
A. works
B. is working
C. has worked
D. had worked BCABA C D C DCDDC
when, while和as的用法
一.when, while, as在时间状语从句中的区别：
①三者均可表示“当……的时候”，如果主句表示的是短暂的动作，而从句表示的是一段时间，三者可通用。

如：
I met Kang Li as / when / while I was walking along the street・当我沿街散步
时碰见了康丽。

②when可以和延续性动词连用，也可以和短暂性动词连用；而while和ms只能和延续性动词连用。

如：
It was snowing when we got to the airport.当我们到达机场时，天正下着雪。

（不能用while）
③as强调主句与从句表示的动作同时发生，as常表示“随着……”；“一边……，一边……；while强调主句表示的动作持续于while所指的整个时间内；when可指主、从句所述动作同时或先后发生。

如：_
As the time went on, the weather got worse・（as 表示''随着. ”之意）
He sang as he went along.他边走边唱。

Please write while I read.我读的时候，请写下来。

When he reached home, he had a little rest.回到家后，他休息了一会儿。

④when用于表示，一……就……”的句型中（指过去的事情）。

somebody had hardly （=scarcely） done ...when. • . = Hardly / Scarcely had somebody
done ...when. •.
①I had hardly / scarcely closed my eyes when someone knoeked at the door. = Hardly / Scarcely had I closed my eyes when some one kno eked at
the door.我刚一闭上眼，抚有人在敲门了。

二.when, while和as都可引导让步状语从句：
①.when引导让步状语从句，意为“尽管，虽然”相当于though或although:
They stopped trying when they might have succeeded next time・
②while引尊让步状语从句，相当于although ,是较为正式的书面语：
While I am willing to go, I would like it better that you went.
③as引导让步状语从句必须倒装，从句中的表语，状语或动词原形置于句首，
若表语为名词，前置时省略冠词。

Child as he is, he knows a lot.
Much as I like it, I will not buy it, for it's too expensive・
Try as he might, he couldn't find a job・
三.when和while可用作并列连词：
①when作并列连词，意为牠突然，正在那个时候”常运用于以下句型中：
Somebody be about to do…when…
Somebody be on the point of doing...when...Somebody be doing..・
when..・
Somebody had done…when..・
We were having a meeting when someone broke in.
We were about to set off on our way, when it suddenly began to rain.
②作并列连词，意为“而，却"，表示对比。

He likes pop music, while I am fond of music・
四.when和as用于原因状语从句中：
®when=since, now that... “既然”
Why do you want a new job when you've got such a good one already?
②意为“因为”，指说话双方都知道的原因。

As he was not ready in time, we went without him.
组题练习：
1.Success came _____ she began to play leading parts in radio plays.
A.While
B. as
C. when
D. if
2.The atmosphere gets thinner and thinner ______ the height increases・
A.When
B. as
C. while
D. since
3.1 was just about to go to sleep _____ there was a loud knock on the door.
A. While
B. when
C. as
D. since
4.They were surprised that a child should work out the problem ____ they
themselves couldn't.
A. When
B. where
C. until
D. while
5.We were swimming in the lake _____ suddenly the storm started.
A. When
B. while
C. until
D. before
6.1 do every single bit of housework _____ my husband Bob just does the dishes
now and then. （04高考广西卷）
A. Since
B. while
C. when
D. as
7.____ I accept that he is not perfect, I do actually like the person.（04 高考江苏卷）
A. While
B. Since
C. Before
D. Unless
8.Jasmine was holidaying with her family in a wildlife park ____ she was bitten on
the leg by a lion.（04 高考上海卷）
A. When
B. while
C. since
D. once
9. ____ modeling business is by no means easy to get into, the good model will
always be in demand.（o4 高考浙江卷）
A. While
B. Since
C. As
D. If
10.All gases and most liquids and solids expand _____ heated.
A. as
B. while
C. before
D. when
IL We have only three books _____ we need five.
A. as if
B. if
C. when
D. even though
12.How can we explain it to you ____ ?
A. while you are listening
B. unless you will listen
C. as you won，t listen
D. when you won，t listen 13. ____ I had to work
to support my family.
A. When I was a little child
B. While I was a little child
C. As I was a little child
D. Before I was a little child
14. ___________ , helicopters flew to the burning building.
A. While the firefighters were trying to control the fire
B.As the firefighters were trying to control the fire
C.As soon as the firefighters were trying to control the fire
D.After the firefighters had controlled the fire
15. T he husband was looking after the baby _________ .
A. after his wife cooked in the kitchen
B.as his wife was cooking in the kitchen
C.when his wife was cooking in the kitchen
D・ while his wife was cooking in the kitchen
16. L ook at the sun. It is shining. ______ if s sunny, let，s go for a walk.
A. as
B. when
C. if
D. as soon as
17. T he sad mother sat on the roadside, shouting _______ she was crying.
A. what
B. when
C. as
D. which
1 & Hardly had we entered the room _____ it began to rain.
A. while
B. as
C. then D・ when
19. __________ , he does get annoyed with her sometimes.(04).
A. Although much he likes her B・ Much although he likes her
C. As he likes her much
D. Much as he likes her
20. _____ years go by, China is getting stronger and richer
. A. When B. As C. While D. Since
Keys: 1-1OCBBDA/B AAAD
11-20CDAAD/ACDDB。