After decades of effort the city is still trying to how to stop smoking in public places

问题补充：

After decades of effort, the city is still trying to how to stop smoking in public places.

A. try out

B. let out

C. figure out

D. run out

答案：

A. try out

B. let out

(答案→)C. figure out

D. run out

解析：考查动词短语辨析。A尝试；B泄漏；C查明，发现；D用完，耗尽；句意：经过几十年的努力以后，这座城市仍然还在如何在公共场所禁止抽烟。故C正确。