Because of wireless service costs plummeting in the last year, and as mobile phones areincreasingly common, many people now using their mobile phones to make calls across awide region at night and on weekends, when numerous wireless companies provideunlimited airtime for a relatively small monthly fee.
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
答案给的是E,我想问
关于D:不可以理解为独立主格吗? 关于E:and前后的时态可以不一致吗?
谢谢大家!
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