all the while
一直,始终from begin to end
He teaches English in the school all the while .他一直在这所学校里教英语。


once in while
时不时,偶尔,间或occasionally
He went to see them once in a while .他偶尔去探望他们。

I haven't seen him for along while .我好久没看见他了。

［同义词］ conj.  as, when
［词源］＜古英语hwil(当…时,和…同时)

1.while用作连词时,表示“在…(过程)中,在…期间”。常用来引导时间状语从句,当主句的主语和while所引导的从句的主语一致时, while从句中的主语、谓语往往可以省去。
2.while还可引导让步状语从句,意思是“虽然,尽管”,含有对比意味。
3.while表示对比关系时,意思是“而,然而”。

You don't want to marry while you are studying.在学习期间,你不要结婚。
While we were talking,he came in.我们正在谈话时,他进来了。
While in prison, he wrote his first novel.他在狱中写出了第一部小说。
While I admint his good point, I can see his shortcomings .虽然我承认他的优点,我还是能看到他的缺点。
Motion is absolute while stagnation is relative .运动是绝对的,而静止是相对的。

while, as, when
参见as条。

while还可用作及物动词,意思是“消磨时间”,常同副词ａｗａｙ搭配。例如:
When I'ｍ free,I play the violin to while away time .我一有空,就拉小提琴来消磨时间。