Stop about the traffic. Just think about what we can do to improve it.A. complainB. to co

问题补充：

Stop about the traffic. Just think about what we can do to improve it.

A. complain

B. to complain

C. complaining

D. complained

答案：

A. complain

B. to complain

(答案→)C. complaining

D. complained

解析：Stop to do sth 是停下手上的事去做另一件事

Stop doing sth 是停止手上正在做的事

停止抱怨交通了，我们想想可以做些什么去改善。所以应该用stop doing，答案选C。