题目

They ________ on the program for almost one week before I joined them, and now we ______ it as no good results have come out so far.       A．had been working; are still working       B．had worked; were still working       C．have been working; have worked          D．have worked; are still working 答案：.A 解析：本题考查几个动词的时态。前一空由于句中所用的是过去时间状语，而且表示的是一种持续进行的动作，所以采用了过去完成进行时。

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