[求助] OG13-134

moontroy

134. Recently implemented "shift-work equations" based
on studies of the human sleep cycle have reduced
sickness, sleeping on the job, fatigue among shift
workers, and have raised production efficiency in
various industries.
(A) fatigue among shift workers, and have raised
(B) fatigue among shift workers, and raised
(C) and fatigue among shift workers while raising
(D) lowered fatigue among shift workers, and raised
(E) and fatigue among shift workers was lowered
while raising

这题正确答案是c, 因为要parallel什么的。

想问while不是连词么，不是副词，后面怎么能跟doing呢，这是个什么结构？多谢。

moontroy

发错了。。。应该是SC版。