一、While作為并列連詞,意思為“而,然而”,表前后意義上的對(duì)比或轉(zhuǎn)折。
例如：There’s plenty of rain in the southeast,while there's little in the northeast.東南部雨量充足,而西北部則很少下雨。
Some people waste food while others haven't enough.有些人浪費(fèi)糧食,然而有些人卻吃不飽。

二、另外while還有別的用法，while引導(dǎo)狀語從句,有以下兩種含義：
1．表示某個(gè)動(dòng)作正在進(jìn)行的同時(shí),另一動(dòng)作也在進(jìn)行之中,這時(shí)主從句都用進(jìn)行時(shí)態(tài),有對(duì)同類的兩個(gè)動(dòng)作進(jìn)行對(duì)比的意味.如：
While I was playing the piano,she was dancing．我在彈鋼琴,她在跳舞.
While Jim is picking apples,Kate is carrying apples to the truck．吉姆正在摘蘋果,凱特正在把蘋果搬到卡車上去.
2．表示某個(gè)動(dòng)作正在進(jìn)行時(shí),又發(fā)生了另一動(dòng)作（該動(dòng)作用一般過去時(shí)）.如：
While I was reading,I fell asleep．我讀著讀著就睡著了.
While we were swimming in the river,we saw a fish jump out of the water．我們正在河中游泳時(shí),看見一條魚躍出了水面.

三、while還有以下幾種常見用法：
1．只要（＝as long as）
There will be life while there is water and air．只要有空氣和水,就會(huì)有生命.
2．而；然而〔表示對(duì)比〕
He is a driver while I'm a teacher．他是司機(jī),而我是老師.
3．雖然（＝although）；盡管〔表示讓步〕
While I see what you say,I can't agree with you．雖然我能理解你說的話,但是我不能同意你.
4．用作名詞,表示“一會(huì)兒或一段時(shí)間”,常與a,the或this等連用.如：
Just wait a while and then I will help you.等一下,我會(huì)來幫你的.
Where have you been all this while?這一陣子你一直都在哪兒?

四、while所引導(dǎo)的時(shí)間狀語從句中的謂語動(dòng)詞只能是延續(xù)性動(dòng)詞。
例如：I met with an old friend of mine while(when) I was walking along the street.