with的用法又有点懵了，求助

红黑蓝调

PREP2-191
For the last five years the Dutch economy has grown faster than Britain, France, or Germany, with the unemployment rate having remained well below that of the other three countries.  
D.    the economy of Britain, France, and Germany, with the unemployment rate that has remained
D选项笔记上的解释为with的逻辑主语是Dutch economy，错误

但下面这道prep2-175 逻辑主语是people，好像不符合呀。。。
Because of wireless service costs plummeting in the last year, and as mobile phones are increasingly common, many people now using their mobile phones to make calls across a wide region at night and on weekends, when numerous wireless companies provide unlimited airtime for a relatively small monthly fee.
A.    Because of wireless service costs plummeting in the last year, and as mobile phones are increasingly common, many people
B.    As the cost of wireless service plummeted in the last year and as mobile phones became increasingly common, many people
C.    In the last year, with the cost of wireless service plummeting, and mobile phones have become increasingly common, there are many people
D.    With the cost of wireless service plummeting in the last year and mobile phones becoming increasingly common, many people are      
E.    While the cost of wireless service has plummeted in the last year and mobile phones are increasingly common, many people are

GGLL1127

PREP 上是解释 这个WITH是做的原因状语 而不是伴随状语吧

红黑蓝调

PREP 上是解释 这个WITH是做的原因状语 而不是伴随状语吧

-- by 会员 GGLL1127 (2011/10/19 11:03:59)

我看到了，是相当于as        这时候就不用考虑逻辑主语咯？

aaroncheng

同样求助with的用法，请牛人前辈出现指点。