Jiaxing is a small city. Therefore to the flow of traffic the government has decided to

问题补充：

Jiaxing is a small city. Therefore, to the flow of traffic, the government has decided to broaden some main streets.

A. speed up

B. build up

C. put up

D. come up

答案：

(答案→)A. speed up

B. build up

C. put up

D. come up

解析：句意，江西是一个小城市。因此，为了加速交通的流动，政府决定拓宽一些大街。speed up加速build up建立put up举起come up上来，根据题意，故选A。