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。