sales of cars up by 30% last year the traffic in Beijing has become increasingly terrible

问题补充：

sales of cars up by 30% last year, the traffic in Beijing has become increasingly terrible.

A. With

B. Since

C. For

D. As

答案：

(答案→)A. With

B. Since

C. For

D. As

解析：句意，随着去年汽车销售增长了30%，北京的交通变得越来越可怕。这里表示“伴随”的意思，而不是表“原因”，故排除B、C和D。