——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．workedB．had workedC．a(chǎn)re workingD．had been working
C
考查時(shí)態(tài)�！坝袔椭麄兏牡暨@種壞習(xí)慣的可行的方法嗎？”“說實(shí)話，非常難。但是我們還正在研究這個(gè)問題。”根據(jù)句意可知，用現(xiàn)在進(jìn)行時(shí)。故選C。
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