一、 while 用作名词时,意为“一段时间,一会儿”.例如：
i stayed there for a short while.
（我在那儿呆了一小会儿.）
the postman came a short while ago.
（邮递员刚刚来过.）
二、 while 用作连词时,有以下几种含义：
1. 意为“当……时候,和……同时”,引导时间状语从句.例如：
you can go swimming while i’m having lunch.
我吃午饭时你可以去游泳。
while i was watching tv, the bell rang.
（我看电视时,铃响了.）
meimei watched tv while she ate her supper.
（梅梅边吃晚饭边看电视.）
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。
2.(表示某一件事是在另一件事发生过程中的某一时间点发生的)当…的时候，在…时
we must have been burgled while we were asleep.
我们睡着时一定让贼入室偷了。
her parents died while she was still at school.
她还在读书时父母就去世了。
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
i sat on the settee to unwrap the package while he stood by
我坐在长椅上打开包裹时他就站在旁边。
3. 意为“虽然,尽管”,一般放句首，引导让步状语从句.例如：
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 modelling business is by no means easy to get into, the good model,male or female, will always be in demand
尽管模特行业绝不是那么容易进入的，但是好的模特，不论男女，总是需要的。
while it was late, he went on working.
（虽然很晚了,但他还在继续工作.）
while he is in poor health, he works hard.
（虽然他身体不好,但他还是努力工作.）
4. 连接两个并列句子,表示“对比”关系.例如：
i looked a bit stiff while they were so lively.
他们都那样活泼，显得我太板了
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。
marianne was tempted to turn the large rooms into traditional french-style salons, while howard was in favour of a typically english look…
玛丽安娜想把这些大房间弄成传统法式客厅的样子，但是霍华德喜欢典型的英式风格。
he went out for a walk, while i stayed at home.
（他出去散步了,而我却呆在家里.）
i like singing while she likes dancing.
（我喜欢唱歌,而她喜欢跳舞.）
you like sports, while i prefer music.
（你喜欢体育,而我更喜欢音乐.）
5. 到…时；直到…为止 （until）
i waited while six o’clock.
我一直等到了六点钟。
三、 while 引导状语从句时,应注意以下几点：
1. while 引导的时间状语从句既可放在句首,也可放在句末；而 while 引导的让步状语从句一般放在句首,不放在句末.另外,也可以从意义上加以区分.例如：
while the news, so far, has been good, there may be days ahead when it is bad.
尽管到现在为止还都是好消息，但是可能过不了几天就会有坏消息传来
while he was tired, he went on working.
（虽然他累了,但他还是继续工作.）
（ while 引导让步状语从句）
while he was tired, he would have a rest.
（他累了就休息一会儿.）
（ while 引导时间状语从句）
2. while 引导让步状语从句时,如果从句的主语和主句的主语相同,那么从句的主语和谓语动词 be 都可以省略.例如：
while he was ill, he went there. （= while ill, he went there.）
（虽然他有病,但他还是去那里了.）
3. while 和 when 都可以引导时间状语从句,但应注意： while 引导的时间状语从句中的谓语动词必须是延续性的动词或表示状态的动词；而 when 引导的时间状语从句中的谓语动词既可以是延续性动词,也可以是非延续性动词.当时间状语从句中的谓语动词是延续性动词时, while 和 when 可以互相替换.例如：
while we were talking, the teacher came in.
（我们正在谈话时,老师进来了.）
the bus had left when we arrived at the bus stop.
（当我们到达车站时,公共汽车已经开走了.）
（ arrive 是非延续性动词,因此,此句中的 when 不能用 while 替换.）
when / while we were having a meeting, our teacher came in.
（我们正在开会时,老师走了进来.）
（ have 是延续性动词,因此,句中的 when 可以用 while 替换.）
while引导的时间状语从句多用进行时态,而when引导的时间状语从句多用一般时态. 例如：while they were talking ,the bell rang.正在他们谈话的时候,上课铃响了.
i was doing my homework when my mother came back home yesterday evening.昨天晚上妈妈回家的时候,我正在做家庭作
4. while 引导的状语从句还可以表示“某个动作正在进行的同时,另一个动作也在进行之中”.例如：
while the teacher was speaking, the students were listening.
（老师讲课时,学生们在听.）
while he was writing, i was reading
i filled the kettle while she was talking and plugged it in
她说话间，我把水壶灌满并插上了电源。
重要习惯用法：
while you’re/i’m etc. at it
趁做某事的时候；顺便；顺带
i’m just going to buy some postcards.’ ‘can you get me some stamps while you’re at it?’
“我正想去买明信片。”“你能顺便给我买些邮票吗？”
四、辨析when as while 【导航词义：当…时】
when conj. 在…时，当…时
〔辨析〕
所引导的状语从句中，谓语可以是延续性动词，也可以是瞬时动词，其动作既可以和主句的动作同时发生，也可以在主句的动作之前或之后发生。
〔例证〕
he got engaged to lucy when travelling last autumn.
去年秋天旅行时，他与露西订了婚。
it was raining when we arrived.
我们到的时候正在下雨。
turn off the switch when anything goes wrong with the device.
如果装置出故障，就把开关关掉。
as conj. 当…时，（正当）…的时候
〔辨析〕
引导状语从句时，侧重指从句中的动作与主句中的动作同时发生或同时进行，一般持续时间不长，其谓语可以是延续性动词，也可以是瞬时动词。
〔例证〕
she was coming in as he was going out.
她进来的时候，他正要出去。
i caught a whiff of perfume as she swept past me.
她从我身边走过时，我闻到一股香水味。
joe jumped onto the bus just as it was pulling away.
正当公共汽车开动时，乔跳上了车。
while conj. 当…时，在…期间
〔辨析〕
指在某事发生之际或发生的过程中，另一事又发生。所引导的状语从句中，谓语应为延续性动词，而不用瞬时动词，强调其动作与主句中的动作同时发生，但持续时间一般较长；有时也可指主句的动作在从句的动作过程中发生。
〔例证〕
don’t interrupt him while he is thinking.
他在思考时别去打搅他。
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。
