since和for的区别用法

since和for的区别用法
since和for的区别用法

since和for的区别用法
since+时间点
for+时间段
Since 用来说明动作起始时间,for用来说明动作延续时间长度.
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,那么正确的含义是什么呢?
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.自从他来到我们学校,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.
这是最常见的一种用法,此处不再多述.
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.
本文开始出现的那个句子就可以译为“自从我离开上海,就再也没有收到他的信.”这种译法常被人们误用,我们不妨再多举几个例子看看：
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.
比较：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.
试比较：1. 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,前者以肯定的语法形式反映着否定的逻辑内容,而后者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.
一、延续性动词和终止性动词的概念
英语中,动词按其动作发生的方式、动作发生过程的长短,可分为延续性动词和终止性动词.
延续性动词表示能够延续的动作,这种动作可以延续下去或产生持久影响.如：learn, work, stand, lie, know, walk, keep, have, wait, watch, sing, read, sleep, live, stay等.
终止性动词也称非延续性动词、瞬间动词或短暂性动词,表示不能延续的动作,这种动作发生后立即结束.如open, close, finish, begin, come, go, arrive, reach, get to, leave, move, borrow,buy等.
二、延续性动词的用法特征
1.延续性动词可以用于现在完成时,其完成时态可与表示"段时间"的状语连用.表示"段时间"的短语有：for two years, during the past three years, since last year, how long等.如：I have learned English since I came here.自从我来到这儿就学英语了.
2.延续性动词不能与表示短暂时间的"点时间"状语连用.如：It raind at eight yesterday morning.(误) rain为延续性动词,而at eight表示"点时间",前后显然矛盾.如果用延续性动词表示一瞬间的动作,可以借助come, begin, get等终止性动词来表示.上句可改为：It began to rain at eight yesterday morning.(正)又如：
-When did you get to know Jack?
-Two years ago.
-Then you've known each other for more than two years.
-That's right.
三、终止性动词的用法特征
1.终止性动词可用来表示某一动作完成,因此可用于现在完成时.如：
The train has arrived.火车到了.
Have you joined the computer group?你加入电脑小组了吗?
2.终止性动词表示的动作极其短暂,不能持续.因此,不可与表示一段时间的状语连用(只限肯定式).如：
(1)他死了三年了.
误：He has died for three years.
正：He has been dead for three years.
正：He died three years ago.
正：It is three years since he died.
正：Three years has passed since he died.
(2)他来这儿五天了.
误：He has come here for five days.
正：He has been here for five days.
正：He came here five days ago.
正：It is five days since he came here.
正：Five days has passed since he came here.
(1)、(2)句中的die、come为终止性动词,不能与表示"段时间"的状语连用.那么,应如何正确表达呢?可以采用下面的四种方法：
(1)将句中终止性动词转换为相应的延续性动词,如上面两例中的第一种正确表达方式.下面列举几例：leave→be away, borrow→keep, buy→have, begin/start→be on, die→be dead, move to→live in, finish→be over, join→be in/be a member of, open sth.→keep sth. open, fall ill→be ill, get up→be up, catch a cold→have a cold.
(2)将句中表示"段时间"的状语改为表示过去确定时间的状语,如下面两例中的第二种正确表达方式.
(3)用句型"It is+段时间+since..."表达原意,如上面两例中的第三种正确表达方式.
(4)用句型"时间+has passed+since..."表达原意,如上面两例中的第四种正确表达方式.
3.终止性动词可用于现在完成时否定式中,成为可以延续的状态,因而可与表示一段时间的状语连用.如：
He hasn't left here since 1986.
I haven't heard from my father for two weeks.
4.终止性动词的否定式与until/till连用,构成"not+终止性动词+until/till ..."的句型,意为"直到……才……".如：
You can't leave here until I arrive.直到我到了,你才能离开这里.
I will not go to bed until I finish drawing the picture tonight.今天晚上直到我画完画,我才上床睡觉.
5.终止性动词可以用于when引导的时间状语从句中,但不可以用于while引导的时间状语从句中.when表示的时间是"点时间"(从句谓语动词用终止性动词),也可以是"段时间"(从句谓语动词用延续性动词).而while表示的是一个较长的时间或过程,从句谓语动词用延续性动词.如：
When we reached London, it was twelve o'clock. (reach为终止性动词)
Please look after my daughter while/when we are away. (be away为延续性动词短语)
6.终止性动词完成时不可与how long连用(只限于肯定式).如：
误：How long have you come here?
正：How long have you been here?
正：When did you come here?

since 代表从 某个时间点 开始 已完成的状态 或 持续的 动作/行为 用完成式
ex i have learned english since 1999
for 代表从 某个时间点 开始到 另一个时间点 持续多久的状态或者动作/行为 也用完成式
ex i have learned english for 12 years .

since
since
[sIns; sins]
《源自古英语“其后”的意思》
连接词
1
a. [常 ever ~,用于表继续之完成式主要子句后] 自从…以后,自…以来,从…起一直
He has been abroad (ever) ~ he parted from me.
自从他离开我后,他一直在海外
I've bee...

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since
since
[sIns; sins]
《源自古英语“其后”的意思》
连接词
1
a. [常 ever ~,用于表继续之完成式主要子句后] 自从…以后,自…以来,从…起一直
He has been abroad (ever) ~ he parted from me.
自从他离开我后,他一直在海外
I've been doing this work (ever) ~ I retired.
自从退休后我一直在做这工作
b. 从做…时候起 (到现在 [那时] 的期间)
The city has changed a lot ~ I have lived here.
自从我住在这里的时候起,这城市已改变了很多
He had not seen her ~ he (had) married.
自从他结婚之后他就一直没见过她
c. (~) 的构句] 自…后 (已过…年)
It is [has been] two years ~ I left school.
自从我离校后已经过了两年
2 既然…,因为…
S~ there's no more time, we must give it up.
既然不再有时间,我们必须放弃那件事
Let's do our best, ~ we can expect no help from others.
既然我们不能指望别人的帮助,我们就尽全力去做吧
介系词
1 a. [常 ever ~,常与表示继续之完成式连用] 自…以来 (一直)
They have been very happy together ever ~ their marriage.
自从他们结婚以来,他们一直快乐地生活在一起
S~ then I had wondered where he lived.
从那时起,我一直在想他住在哪里
S~ when have you lived here?.
从什么时候起你就住在这里了?
b. 从…以后 (时间[期间] (有多久)
It's a long time ~ her death.
她去世后已经过了很久
She has changed a good deal ~ her sickness.
自从她生病后她已经改变了很多
c. (口语)从发明[发现]…的时代以来
He is the greatest novelist ~ Henry James. (
口语)他是自亨利.詹姆斯以来最伟大的小说家
副词
(无比较级、最高级)
1
a. [常 ever ~] (那时) 以来 (一直) ,从那时以后 (直到现在)
He went to America twenty years ago and has stayed there ever ~.
二十年前他去了美国,从此就一直留在那里
b. 从那时起 (到现在 [那时] 的这一段期间) ,其后
I have not seen him ~.
从那时候起我一直没见过他
2 [常 long ~] (从现在起) (几年) 前
long ~
很久以前,好久以前
not long ~
不久以前,未久
He has long ~ arrived.
他好久以前就到了; 他到了很久了
for
[轻读)fL; fə; (重读)fɒr:fɒ:]
介系词
A
1 为了…,对…
give one's life ~ one's country
为国家捐躯 [牺牲生命]
work ~ an oil company
为一家石油公司工作,在一家石油公司上班
Can I do anything ~ you?.
我能为你做什么事 [替你服务] 吗?
Smoking is not good ~ your health.
吸烟对你的健康有害
It was fortunate ~ you that he was there.
他在那里对你来说是幸运的
2 a. 为纪念…,为…
A party was held ~ them.
设宴招待他们
b. (美.文语)由于…,以…命名 [取名] ( (英) after)
He was named James ~ his grandfather.
他以祖父的名字被命名 [取名] 为詹姆斯
3 为给… (的) ,…收的
a present ~ you
给你的礼物
I've got some good news ~ you.
我有一些好消息要告诉你
Who is it ~?.
那是给谁的?
Bill, there's a call ~ you.
比尔,有人打电话给你
She bought a new tie ~ Tom.
她为汤姆买了一条新领带
4 向…,往…去 (的) ; 为进入… (的)
start [leave] ~ India
向印度出发,动身往印度去
Is this train ~ Edinburgh?.
这班列车是开往爱丁堡的吗?
Did you get the tickets ~ the game?.
你买到那场比赛的入场券了吗?
5 为了…,以…为目的; 打算成为 …
go ~ a walk [a swim]
去散步 [游泳]
I bought the book ~ studying at home.
为了在家自修而买了那本书
What did you do that ~?.
你为什么做那件事?
He volunteered ~ the task.
他志愿去做那件工作
6 为获得… (的) ,为 (求) …
an order ~ tea
茶叶的订单
send ~ a doctor
派人去请医生
wait ~ an answer
等待答覆
We wrote to him ~ advice.
我们写信向他求教
Everyone wishes ~ happiness.
大家都希望幸福
He was thirsty ~ knowledge.
他渴望求知
7 为准备… (的) ,为保持 [治疗] … (的)
study ~ an exam
为考试而用功
→for one's LIFE
a good remedy ~ headaches
治疗头痛的良药
The meeting is at 6:30~7.
为七点聚会请于六点半出席
8
适合… (的) ,…用 (的)
a cupboard ~ dishes
放食器用的橱柜
(食橱,碗橱)
a time ~ action (
适于) 行动的时刻
a room ~ study
读书用的房间
(书房)
a magazine ~ boys
适合少年的杂志
(少年杂志)
9 在 <何时、何日> (的) ; 在…时候 (的) ; 为庆祝…
an appointment ~ the afternoon
下午的约会
The wedding has been fixed ~ May 5th.
婚礼订于五月五日
She was Miss Universe ~ 1983.
她是 1983 年的环球小姐
I gave him a baseball mitt ~ his birthday.
为祝贺他的生日,我送给他一只棒球手套
10 在…期间 (一直) ; (预定的) …期间
~ hours [days, years]
几小时 [天,年] 之久; 有 (好) 几小时 [天,年]
~ the last ten years
过去十年来; 在最近的十年期间
~ all time
永久
~ days (and days) on end
连续好几天
stay there (~) three weeks
在那里停留三周
walk (~) three miles
走三哩路
The snowy weather lasted (~) the whole time we were there.
我们在那里的整个期间一直都是下雪的天气
I haven't spoken to her ~ two months.
我没有和她说话已有两个月
F~ miles and miles there was nothing but sand.
有好几哩之远除沙外别无他物
He didn't work ~ a long time.
他很久没有工作
They went down to the sea ~ a [the] day.
他们去海边一天
The TV station stopped broadcasting ~ the day.
电视公司结束了当天的播放
That's all ~ today.
今天到此为止
11 计…,达…
a check ~ $10
一张十元的支票
Put me down ~.
￡5. 请记下我的五镑份
12 代替… (的) ,为了…
a substitute ~ butter
奶油的代用品
speak ~ another
代替他人说话,代言
Say hello ~ me.
请代我问候
13 a. 表示…,表达…
What's (the) German ~ 'water'?.
德语“水”怎么表达 [怎么说] ?
b. 代表…
the Member of Parliament ~ Liverpool
代表利物浦 [由物浦地方选出] 的国会议员
14 交换…; 为<商品等>; 以…的金额 [价钱]
He gave her his camera ~ her watch.
他用自己的相机交换她的手表
I paid $50 ~ the camera.
我付了五十美元买那相机
I bought it ~ $50.
我以五十美元买了那个东西
These eggs are 2 dollars ~ 10 [10 ~ 2 dollars].
这些鸡蛋是十个二美元
15 对 <好意、成果等> ,作为…的报答
five points ~ each correct answer
每一正确答案给五分
give blow ~ blow
以打还打,挨了打就打回去
→ an EYE for an eye
We thanked him ~ his kindness.
我们对他的好意致谢
16 支持… (的) ,为…
(
←→ against)
vote ~ Smith
投票支持史密斯
Are you ~ or against the war?.
你赞成或反对战争?
She's all ~ going shopping.
她完央佻成去购物
I'm ~ calling it a day.
今天的工作就到此为止

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since http://dict.baidu.com/s?wd=since for http://dict.baidu.com/s?wd=for 要学会自己查字典，百度一下，对你又帮助的。

since+具体的时间
for+一段时间
They have learnt English since 2006. 他们自从2006年就学习英语了。
They have learnt English for 5 years. 他们学习英语已经5年了。

八年级下册6单元的，自己百度去吧

Since 用来说明动作起始时间，for用来说明动作延续时间长度。例如：
I have lived here for more than twenty years.我住在这儿二十多年了。
I have lived here since I was born. 我从出生起就住在这儿了。
注意：并非有for 作为时间状语的句子都用现在完成时。
I wor...

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Since 用来说明动作起始时间，for用来说明动作延续时间长度。例如：
I have lived here for more than twenty years.我住在这儿二十多年了。
I have lived here since I was born. 我从出生起就住在这儿了。
注意：并非有for 作为时间状语的句子都用现在完成时。
I worked here for more than twenty years. （我现在已不在这里工作。）
I have worked here for many years.（现在我仍在这里工作。）
注意：用句型转换的方法，很容易排除非延续动词在有for/since结构的完成时中的误用。

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