PREP08-Q223 和曼哈顿的解释矛盾？请赐教！。。

毛毛的臭脚丫

新PREP-Q223

After several years of rapid growth, the health 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 it then proved unable to handle the increase in business, falling months behind in its payment to

B. while 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 its paying

D. but then proving unable 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

答案是E，但是曼哈顿上的P147页上对BUT的用法有两个例子
I study hard but take breaks.
I study hard , but i take breaks.
注意两个句子的逗号用法和BUT后面的主语关系，感觉曼哈顿的解释和这题的答案矛盾。请指教。。。。。迷茫了。。

毛毛的臭脚丫

画线句子是while it then proved unable to handle the increase in business, falling months behind in its payment to，不包括while前的逗号

毛毛的臭脚丫

顶。。

Gail小M

1) I study hard but take breaks.  
2)I study hard , but i take breaks.-->  since there is a comma, thus we repeat the subject for CLEARNESS.
we cannot eliminate a choice just for this reason.

E: without subject, but we can still figure out the subject ( which is the SUBJECT of the previous sentence)

but if there is a correct answer like this: but then it proved unable to handle the increase in business, falling months behind in paying.---> u may choose this one.

Gail小M

another example for U.

Scientists believe that unlike the males of most species of moth, the male whistling moths of Nambung, Australiacall female moths to them
, using acoustical signals, rather than olfactory ones, and attract their mates during the day, rather than at night.

same situation. does not repeat the subject.

毛毛的臭脚丫

十分感谢！！！