◎ 题干
—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.workedB.had workedC.are workingD.had been working
◎ 答案
查看答案
◎ 解析
查看解析
◎ 知识点
    根据n多题专家分析,试题“—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…”主要考查了你对  【一般现在时】【将来进行时】【过去完成进行时】【过去将来时的被动语态】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。