—Is there any possible way to help them get rid of such a bad habit?—To tell the truth it

问题补充：

—Is there any possible way to help them get rid of such a bad habit?

—To tell the truth, it’s very hard. But we on this problem, trying to improve the situation .

A. worked

B. had worked

C. are working

D. had been working

答案：

A. worked

B. had worked

(答案→)C. are working

D. had been working

解析：句意：--有可行的方法来改掉坏的习惯？--说句实话，很难。但是我们正在解决这个问题，试图提高现状。从第一句可以看出现在还没有改掉习惯，所以应是现在正在想法去解决，故选C。