while

1. CONJ If something happens while something else is happening, the two things are happening at the same time. 当…的时候 (表示两事同时发生)

They were grinning and watching while one man laughed and poured beer over the head of another. 当一个男人大笑着将啤酒倒在另一个男人头上时，他们正边看边咧着嘴笑。

I sat on the chair to unwrap the package while he stood behind me. 我坐在椅子上打开包裹，当时他就站在我身后。

2. CONJ If something happens while something else happens, the first thing happens at some point during the time that the second thing is happening. 正值…之时 (表示一件事是在另一件事发生过程中的某个时间发生的)

The two ministers have yet to meet, but may do so while in New York. 两位部长还未会面，但他们在纽约期间可能会见面。

3. CONJ You use while at the beginning of a clause to introduce information that contrasts with information in the main clause. 而 (用于从句之首，引出与主句内容相对比的信息)

Most digital camera owners are male, while women prefer film. 大部分数码相机的主人都是男性，而女性偏爱用胶卷。

4. CONJ You use while, before making a statement, in order to introduce information that partly conflicts with your statement. 虽然 (用于发表陈述之前，引入和陈述内容部分矛盾的信息)

While the news, so far, has been good, there may be days ahead when it is bad. 虽然到目前为止都是好消息，但是可能过几天就有坏消息了。

CONJ

1. N-SING A while is a period of time. 一段时间

They walked on in silence for a while. 他们默默地走了一会儿。

He was married a little while ago. 他前不久刚结了婚。

2. PHRASE You use all the while in order to say that something happens continually or that it happens throughout the time when something else is happening. 一直

All the while the people at the next table watched me eat. 邻桌的人一直在看着我吃东西。

3. once in a while→see once

4. worth your while→see worth