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.
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:考查时态。“有帮助他们改掉这种坏习惯的可行的方法吗?”“说实话,非常难。但是我们还正在研究这个问题。”根据句意可知,用现在进行时。故选C。