扎兰屯河西新区2017:when和while的区别是什么？

①when意为"在……时;当……时",可表示"点时间"或"段时间",从句谓语可以是终止性动词,也可以是延续性动词。例如:
When I got home, he was having supper.
③while只可表示"段时间",从句谓语只限于延续性动词。例如:
While I was sleeping, my father came in.
注:从句谓语是持续性动词时,when、while和as可以互换?主?从句谓语都是终止性动词时,when与as可互换?从句谓语表示状态时,通常用while。

①when意为"在……时;当……时",可表示"点时间"或"段时间",从句谓语可以是终止性动词,也可以是延续性动词。例如:
When I got home, he was having supper.
③while只可表示"段时间",从句谓语只限于延续性动词。例如:
While I was sleeping, my father came in.
注:从句谓语是持续性动词时,when、while和as可以互换?主?从句谓语都是终止性动词时,when与as可互换?从句谓语表示状态时,通常用while。

when引导的从句，主句与从句的动词是一短一长，而while前后都是长动作，比如I am watching TV ,while my mother is reading a book.

While强调两个动作同时进行，也可以表转折。

①when意为"在……时;当……时",可表示"点时间"或"段时间",从句谓语可以是终止性动词,也可以是延续性动词。例如:
When I got home, he was having supper.
③while只可表示"段时间",从句谓语只限于延续性动词。例如:
While I was sleeping, my father came in.
注:从句谓语是持续性动词时,when、while和as可以互换?主?从句谓语都是终止性动词时,when与as可互换?从句谓语表示状态时,通常用while。
when和while

when和while都可用作从属连词，表示时间，意思都是“当（在）……的时候”，但二者之间有区别：

when的含义是 at or during the time that，既可用于指一点时间（从句的谓语动词需用终止性动词），也可用于指一段时间（从句的谓语动词用延续性动词），从句与主句里面的谓语动词所表示的动作或状态能同时发生（此时，when可用while代替），或一先一后分别发生。例如：

He wants to help people when they are ill．

他想在人们生病的时候帮助他们。

When he got to Shanghai, the ship had already set off．

他到达上海时，轮船已经开走了。

While的含义是 during the time that, 只能用于指一段时间（从句的谓语动词必须是延续性的），从句与主句里面的谓语动词所表示的动作只能同时发生（此时，while可用when代替），不能一先一后分别发生。例如：

One day while they were working in the fields, some farmers saw something strange in the sky．

有一天，农民在田间劳动的时候，看见空中有些奇怪的东西。

While I was reading , my mother was washing clothes．

我读书时，我妈妈在洗衣服。

这两个词还可用作并列连词。when是“在那时”或“这时突然”（and just at that time）的意思，用来连接两个并列分句，有时when分句之前有逗号把前后两个分句分开。例如：

An Arab was walking along through the desert when he met two men．

有个阿拉伯人正独自在沙漠里行走，这时他碰见了两个人。

I stay till sunset, when it began to rain．

我一直待到太阳下山，天开始下雨了。

while意为“而”。“却”，表示对照关系。例如：Instead, he asked his father why he was not able to hatch chickens while hens could.他反而问他父亲，为什么他不能孵出小鸡，而母鸡却能孵出小鸡。
具体你可以参考这一段。
when，while，as引导时间状语从句的区别
when，while，as显然都可以引导时间状语从句，但用法区别非常大。
一、when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。
① Why do you want a new job when youve got such a good one already？（get为短暂性动词）你已经找到如此好的工作，为何还想再找新的？
②Sorry，I was out when you called me．（call为短暂性动词）对不起，你打电话时我刚好外出了。
③Strike while the iron is hot．（is为延续性动词，表示一种持续的状态）趁热打铁。
④ The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。
二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while和as从句的谓语动作必须是和主句谓语动作同时发生。
1．从句动作在主句动作前发生，只用 when。
①When he had finished his homework，he took a short rest．（finished先发生）当他完成作业后，他休息了一会儿。
②When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时，客人们已经离开了。
2．从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。
①When ／While ／As we were dancing，a stranger came in．（dance为延续性动词）当我们跳舞时，一位陌生人走了进来。
②When ／While ／As she was making a phonecall，I was writing a letter．（make为延续性动词）当她在打电话时，我正在写信。
3．当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用 as。这时，as常表示“随着……”；“一边……，一边……”之意。
① As the time went on，the weather got worse．（as表示“随着……”之意）
② The atmosphere gets thinner and thinner as the height increases．随着高度的增加，大气越来越稀薄。
③As years go by，China is getting stronger and richer．随着时间一年一年过去，中国变得越来越富强了。
④The little girls sang as they went．小姑娘们一边走，一边唱。
⑤The sad mother sat on the roadside，shouting as she was crying．伤心的妈妈坐在路边，边哭边叫。
4．在将来时从句中，常用when，且从句须用一般时代替将来时。
①You shall borrow the book when I have finished reading it．在我读完这本书后，你可以借阅。
②When the manager comes here for a visit next week，Ill talk with him about this．下周，经理来这参观时，我会和他谈谈此事。
三、when用于表示“一……就……”的句型中（指过去的事情）。
sb．had hardly（＝scarcely） done sth．when．．．＝Hardly ／ Scarcely had sb．done sth．when．．．
①I had hardly ／scarcely closed my eyes when someone knocked at the door．＝Hardly ／ Scarcely had I closed my eyes when someone knocked at the door．我刚一闭上眼，就有人在敲门了。
②I had hardly ／scarcely entered my room when the telephone rang．＝Hardly ／Scarcely had I entered my room when the telephone rang．我刚一走进房门，电话就响了。

when
[(h)wen]
conj.
就在那个时候, 在...的时候
adv.
什么时候, ...的时候
pron.
什么时侯, 那时

when
[wen; (?@) hwen]
adv.
什么时候
When can you come?
你什么时候能来？
当…的时候
at the time when we met
在我们见面的时候
I lived in this village when I was a boy.
当我还是个孩子的时候我住在这个村庄里。

when
conj.
…的时候
Edison was not a good student when he was a young boy.
爱迪生小时候不是一个成绩好的学生。
When the plane arrived, some of the detectives were waiting inside the main building while others were waiting on the airfield.
当飞机抵达时,一部分侦探等在主楼里面,而另一部分则等在停机坪上。
When I came home my wife was cooking dinner.
我回家时，妻子在做晚饭。
如果；要是；既然
I can't tell you when you won't listen.
既然你不想听，我就不告诉你了。
其实
He stopped trying, when he might have succeeded next time.
他不再试了，其实他可能下一次就成功。

hardly when
刚…就
Hardly had I opened the door when he told me.
我刚开开门，他就告诉了我。
(= scarcely when)

when
pron.
什么时候
When else shall we meet again, if August 1st is not convenient for you?
要是八月一日对你不方便,那么另外什么时候再碰头呢?
He then asked when Mr Gilbert would be allowed to go home.
然后他又问,什么时候可以允许吉尔伯特先生回家。
Since when have he had a car?
他从什么时候起开始有了一辆汽车？
那时
She wrote a month ago， since when we've heard nothing.
一个月前她来过信，从那时起我们就没听到过她的消息。
The Ambassador's wife went on asking questions, when she suddenly noticed a big hole in her husband's hat.
大使的妻子继续问了好多问题,突然她发现丈夫帽子上有个洞。

when
AHD:[hwµn, wµn]
D.J.:[hwen, wen]
K.K.:[hwWn, wWn]
adv.
At what time:
什么时候：
When will we leave?
我们什么时候离开?
when
conj.
At the time that:
在…的时候：
in the spring, when the snow melts.
在春天，当雪融化的时候
As soon as:
一…就…：
I'll call you when I get there.
我一到那里就给你打电话
Whenever:
无论什么时候：
When the wind blows, all the doors rattle.
只要风一吹，这门就吱嘎作响
During the time at which; while:
在…期间，当…时：
When I was young, I was sick all the time.
在我小时候我总是生病
Whereas; although:
虽然，尽管：
She stopped short when she ought to have continued.
尽管她应该继续下去，她却突然停住了
Considering that; if:
考虑到，如果：
How can he get good grades when he won't study?
他不用功的话怎么拿高分呢?
when
pron.
What or which time:
什么时候：
Since when has this been going on?
从什么时候起事情象这样?
when
n.
The time or date:
时间或日期：
Have they decided the where and when?
他们已经定下来地点和时间了吗?

Middle English
中古英语
fromOld English hwenne
源自古英语 hwenne
*See Also : k In Appendixo-

In informal style when is often used after be in definitions: A dilemma is when you don't know which way to turn. The construction is useful, but it is widely regarded as incorrect or as unsuitable for formal discourse. In formal style there is no alternative but to rephrase such definitions to avoid is when: A dilemma is a situation in which you don't know which way to turn. You are in a dilemma when you don't know which way to turn.
在非正式文体中 when常在定义中用在 be后面： 进退两难就是当你不知道该走哪条路的时候。这个结构是有用的，但被广泛认为它对正式交谈来说是不正确的或者是不合适的。在正式文体中没有替代词，只能改变措辞以避免 is when： 进退两难就是这样一个你不知道该怎么办的处境。当你不知道你该做什么时你就处于进退两难的维谷了

when
[(h)wen]
adv.
[疑问副词]什么时候, 何时
[关系副词]当...时
When will he come?
他什么时候来?
It was a time when motorcars were rare.
那是汽车很罕见的时代。
I still remember the night when Nanjing was liberated.
我还记得南京解放那天晚上的情景。

when
[(h)wen]
conj.
当...时
一... 就...
如果
虽然; 然而; 可是
既然
考虑到; 那时; 然后
It was raining when we started.
我们动身时正下着雨。
We'll start when the team leader comes.
队长一来, 我们就出发。
Turn off the switch when anything goes wrong with the machine.
如果机器发生故障, 就把电门关上。
We have only three books when we need five.
虽然我们需要五本书, 却只有三本。
Why use wood when you can use plastic?
既然能用塑料, 为什么还要用木料?
We played outside till sunset, when it began to rain.
我们在户外一直玩到太阳下山, 那时天下起雨来了。
when
[(h)wen]
pron.
[疑问代词]什么时候
[关系代词]那时
Since when have you been here?
你从何时起就在这个地方的?
We came a week ago, since when the weather has been bad.
我们一星期前来到这里, 从那时起天气一直不好。
when
[(h)wen]
n.
(事件发生的)时间 the when and where of an act 行为发生的时间和地点
Tell me the when and the why (=reason) of it.
请告诉我时间和原因。

whenissued
adj.
(股票, 证券)虚股的
whenness
n.
时间性[关系]

when
当时候;何时

when
AHD:[hwµn, wµn]
D.J.:[hwen, wen]
K.K.:[hwWn, wWn]
adv.
At what time:
When will we leave?
when
conj.
At the time that:
in the spring, when the snow melts.
As soon as:
I'll call you when I get there.
Whenever:
When the wind blows, all the doors rattle.
During the time at which; while:
When I was young, I was sick all the time.
Whereas; although:
She stopped short when she ought to have continued.
Considering that; if:
How can he get good grades when he won't study?
when
pron.
What or which time:
Since when has this been going on?
when
n.
The time or date:
Have they decided the where and when?

Middle English
fromOld English hwenne
*See Also : k In Appendixo-

In informal style when is often used after be in definitions: A dilemma is when you don't know which way to turn. The construction is useful, but it is widely regarded as incorrect or as unsuitable for formal discourse. In formal style there is no alternative but to rephrase such definitions to avoid is when: A dilemma is a situation in which you don't know which way to turn. You are in a dilemma when you don't know which way to turn.

when
n.在...时候

when
什么时候;adv.什么时候

when
什么时候;adv.什么时候

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

while
[(h)wail]
n.
一会儿, 时间
conj.
当...的时候, 虽然
vt.
消磨
prep.
<古><方>直到

while
[waIl; (?@) hwaIl]
n.
一会儿
a long while
好长一会儿
A short while ago, however, he became a busdriver and he has not regretted it.
可是,不久前他当了一名公共汽车驾驶员,而且他不后悔。

once in a while
有时；偶而
worth one's while
值得；有价值

while
conj.
…的时候
While in Vienna he studied music.
他在维也纳时学习音乐。
While he was eating, I asked him to lend me $2.
当他正在吃饭时,我请他借给我二英镑。
While two detectives were keeping guard at the door, two others opened the parcel.
这时两个侦探把着门,另外两个打开包裹。
While I read, she sang.
我看书时，她在唱歌。
I met her while I was at school.
当我在学校的时候我遇见了她。
虽然；但是
While I understand what you say, I can't agree with you.
虽然我理解你的意思，但我还是不同意。
You like tennis, while I'd rather read.
你爱打网球，但我爱看书。
(= whilst)

while
vt.
whiled, whiling
（与away连用） 消磨；度过
They while away many afternoons on the beach.
他们在海滩消磨了许多个下午。
while
adv.
（前面与表示时间的词连用）在…时候
the summer while I was abroad
我出国的那个夏天

while
AHD:[hwºl, wºl]
D.J.:[hwail, wail]
K.K.:[hwa!l, wa!l]
n.
A period of time:
一段时间：
stay for a while; sang all the while.
停留下会儿；一直都在唱歌
See: awhile
The time, effort, or trouble taken in doing something:
费时做一件事情的花费时间、努力或工夫：
The project wasn't worth my while.
这项方案不值得我花工夫，
while
conj.
As long as; during the time that:
只要；在…时间里：
It was lovely while it lasted.
当它开着的时间它是很惹人喜爱的
At the same time that; although:
在…同时；尽管，虽然：
While the grandparents love the children, they are strict with them.
“虽然祖父母们都爱他们的孩子，但却对他们要求严格”
Whereas; and:
然而；而，而且：
The soles are leather, while the uppers are canvas.
鞋跟是皮的，而鞋面是帆布的，
while
v.tr.
whiled; whil.ing; whiles;
To spend (time) idly or pleasantly:
消磨闲散或轻松地消磨时间：
while the hours away.
消磨时光

Middle English
中古英语
fromOld English hwºl
源自古英语 hwºl
*See Also : k In Appendixei…-

while
[(h)wail]
n.
时间; 一段时间, 一会儿
Wait a while.
等一会儿。
It took a long while to do the work.
做这个工作花了许多时间。
What have you been doing all this while?
这一阵子你一直在做什么?

while
[(h)wail]
conj.
当...的时候, 和...同时; 只要
但是, 然而
虽然; 尽管
half-turn while in hanging
悬垂转体180°
Write while I dictate.
当我口述时请你记下。
Some people like coffee, while others like te
adj.
有些人喜欢咖啡, 而有些人喜欢茶。
While he loves his students, he is very strict with them.
虽然他爱他的学生, 可是他对他们很严格。
prep.
[古]到...时候止, 直到...
vt.
消磨, 闲混(时间)(away)

a good [long, great] while
长[许]久
a little while
不久, 一会儿
a while ago
方才, 刚才
after a while
不久, 过一会儿
all the while
始终, 一直
at whiles
有时, 时常
between whiles
间或, 时或
every little while (=at whiles)
有时, 时常
for a [one] while
暂时
in a little while
不久, 没一会儿
make it worth sb.'s while
酬谢某人, 贿赂某人
the while [whilst]
(与此)同时, 在此期间
while you are about it
[口]顺便, 在你做这个的同时
worth (one's) while
值得的; 值得花费时间, 值得一干; 有益的

while
当的时候

while
AHD:[hwºl, wºl]
D.J.:[hwail, wail]
K.K.:[hwa!l, wa!l]
n.
A period of time:
stay for a while; sang all the while.
See: awhile
The time, effort, or trouble taken in doing something:
The project wasn't worth my while.
while
conj.
As long as; during the time that:
It was lovely while it lasted.
At the same time that; although:
While the grandparents love the children, they are strict with them.
Whereas; and:
The soles are leather, while the uppers are canvas.
while
v.tr.
whiled; whil.ing; whiles;
To spend (time) idly or pleasantly:
while the hours away.

Middle English
fromOld English hwºl
*See Also : k In Appendixei…-

while
【软】当

while
期间

while
正当...的时候;n.一段时间

while
正当...的时候;n.一段时间

while
正当...的时候;n.一段时间

while
一会儿；当…的时候；而

while
n.一会儿