新prep223，求while和but 用法区别

pfullsomer

（1）
GWD-23-Q23
After several years of rapid growth, the healthy care company became one of the largest health care providers in the metropolitan area, while it then proved unable to handle the increase in business, falling months behind in its payment to doctors and hospitals.

A    while[/url][CH1]
it then proved unable to handle the increase in business, falling months behind in its payment to
B    while[/url][CH2]
it then proved unable to handle the increase in business and fell months behind in its payment to
C     but then it proved unable to handle the increase in business, falling months behind in [url=]its paying[/url][CH3]
D    but then [url=]proving unable[/url][CH4]
to handle the increase in business, falling months behind in paying

E    but then proved unable to handle the increase in business, falling months behind in paying

E the best

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[CH1]承前转折用but

[CH2]同A

[CH3]one’s doing

[CH4]but后面接句子

我的问题是：

1.but 和while 用法，区别，什么时候用while？

2.one's doing一定错吗？为何？

谢谢牛牛指点

sbjqbS

You use while at the beginning of a clause to introduce information which contrasts with information in the main clause.

注意：at the beginning

shlshing

umm...在表concession時, although=while

pfullsomer

有没有人给出更好的解释？ while和but？

bloomers

我的意思是,while 也有转折的意思,但BUT更加平行.GAMT经常考的是平行,所以先看平行.没错就OK啦