Q1.

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.

筒子们，俺咋也想不通为啥B不对，论坛里也没搜到关于B的解释。as ……and as ……不是挺工整平行的么？是不是因为mobile phone incresingly common 是一个持续性的状态不能用一般过去时？问问大家的看法，谢谢！

edmundshi and dalphia,

very very thanks~!

光顾着和as ……as 较劲了，都没研究题目后面，汗啊……