用法如下：
1.表示时间：当……时候
（1 ）when（当……的时候），引导的时间状语从句的谓语动词可以是延续性动词，也可以是瞬间动词。从句动作可与主语动作同事发生，也可在其后发生。当从句的谓语动词可以是延续性动词时when可以用while替换：
I was reading a book when she came into my room.
(come 是瞬间动词，只能用when引导，不能用while)
I often missed my home when(while) I lived in New York.
（live是延续性动词，when可用while代替）
Her parents died while she was still at school.
她还在读书时父母就去世了。
They were grinning and watching while one man laughed and poured beer over the head of another...
当一个男人大笑着把啤酒倒在另一个人头上时，他们都在乐呵呵地看着。
Give me your hand while we cross the road.
过马路时拉着我的手。
I'll keep you company while you're waiting.
你等待时我会陪伴你。
We must strike while the iron is hot. 我们要趁热打铁。
Stand still while I take your photograph. 我给你拍照时站着不要动。
Don't interrupt him while he is thinking.
他在思考时别去打搅他。
She hates anyone listening while she is telephoning. 她打电话时不愿让任何人听。
----I’m going to the post office.
---While you’re there, can you get me some stamps?
----我要去邮局。
---你在那里的时候，能给我买些邮票吗？
（2）when和while的区别还在于：while引导的时间状语从句多用于进行时态，而when引导的时间状语从句多用于一般时态。
While they were talking, the bell rang. 正在他们谈话的时候，上课铃响了。
While I was waiting at the bus stop, three buses went by in the opposite direction.
我在公共汽车站等车时，对向驶过了三辆公共汽车。
You can go swimming while I'm having lunch.
我吃午饭时你可以去游泳。
Most students face the problem of funding themselves while they are studying.
大多数学生在求学期间都会面临经济来源的问题。
While my wife was reading the newspaper, I was watching TV.
当我妻子在看报纸的时候，我在看电视。
2.while（并列连词）表示对比或相反。相当于whilst：
While my mother was reading the newspaper, I was watching TV.(read是延续性的动词，read和watch同事发生)
I like playing football while you like playing basketball.
我喜欢踢足球，而你喜欢打篮球。（对比）
While their country has plenty of oil, ours has none.
他们国家有充足的石油，而我们国家却没有。
I’d like to study law at university while my cousin prefers geography.
我想在大学里学法律，而我表哥更希望学的是地理。
In some place women are expected to earn money while men work at home and raise their children.
在一些地方，女性被期望赚钱，而男性则在家工作并抚养孩子。
While Tom's very good at science, his brother is absolutely hopeless.
汤姆很擅长理科，而他的兄弟绝对是不可救药。
The cost of living in Glasgow is among the lowest in Britain, while the quality of life is probably one of the highest.
格拉斯哥的生活成本是英国最低的，而生活质量可能是最高的。
He likes pop music，while I am fond of folk music.
他喜欢流行音乐，而我喜欢民间音乐。
Kids talk frequently about what they can do，while many adults do the opposite， tending to talk about what they can't .
孩子们经常谈论他们能做什么，而许多成年人则相反，倾向于谈论他们不能做的。
Some people waste food while others haven’t enough. 一些人糟踏食物而另一些人却食不果腹。
I went swimming while the others played tennis. 我去游泳，而其余的人则去打网球了。
Prices are rising sharply, while incomes are lagging far behind. 物价飞涨而收入却远远落后。
注：这样用时，while引出的句子通常位于末，但有时也可位于句首。如：
While most children learn to read easily, some need extra help. 大多数儿童学会阅读很容易，有一些儿童却需要特别帮助。
While Deauville is a holiday resort, Trouville is more of a working town. 特维尔是个度假胜地，而特鲁维尔更多的却是个工业城市。
There’s no way of knowing why one man makes an important discovery while another man, also intelligent, fails.
没有办法知道为什么一个人做出了重要的发现，而另一个同样聪明的人却失败了。
3.表示让步关系(used at the beginning of a sentence 用于句首)：虽然，尽管相当于although
While I am willing to help, I do not have much time available.
尽管我愿意帮忙，但是没有多少时间。
While the numbers of such developments are relatively small, the potential market is large.
尽管这种增长的数量相对较小，但是潜在的市场是巨大的。
While her observations may be true about some men, they could hardly apply to the entire gender.
虽然她的评论就某些男人而言可能是正确的，但绝不适用于所有男性。
While I really don’t like the art, I find his work impressive.
虽然我真的不喜欢这门艺术，但我觉得他的作品令人印象深刻。
While the Internet is of great help, I don’t think it’s a good idea to spend too much time on it.
虽然互联网有很大的帮助，但我不认为花太多时间在它上面是个好主意。
While I accept that he is not perfect, I do actually like the person.
虽然我承认他并不完美，但我确实喜欢这个人。
While I did well in class, I was a poor performer at games. 虽说我学习不错，我运动却不行。
While a few became richer, many did not. 虽然一些人变得更富有了，但多数人并非如此。
While the work was difficult, it was interesting. 虽然工作有难度，但很有趣。
While we don’t agree we continue to be friends. 尽管我们意见不同，我们还是朋友。
While online shopping has changed our life，not all of its effects have been positive.
尽管网上购物已经改变了我的生活，但并非它所有的影响都是正面的。
While she is a top student， she has some shortcomings.
虽然她是一名优等生，但她也有一些缺点。
While the Internet is bridging the distance between people， it may also be breaking some home or will cause other family problems.
虽然互联网正在拉近人们之间的距离，但它也可能破坏一些家庭，或者会引发其他家庭问题。
While the work was difficult, it was interesting. 虽然工作有难度，但很有趣。
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。
4.连词，只要（as long as，引导条件状语从句。）
While there's life there's hope.
只要活着就有希望。
5.while+v-ing/v-ed/adj./介词短语
即主句与从句主语相同，且从句谓语动词含有动词be时，通常可省略从句主语和动词be。如：
While (he was) in prison, she wrote her first novel. 她在狱中写出了第一部小说。
He had strayed from home while still a boy. 他小时候就离开家到处流浪了。
He fell asleep while (he was) doing his homework. 他做着功课就睡着了。
I was only listening to the radio with half an ear, while (I was) preparing some food. 我正在做吃的东西，没太留心听收音机。
She got married while working as a waitress.
她在饭店当服务生期间结婚了。
Pat killed time by watching TV while waiting for her.
帕特在等她时边看电视边打发时间。
The singer was discovered while still at school.
这个歌唱家在上学的时候就受到赏识了。