问题
选择题
They _________ on the program for almost one week before I joined them, and now we are still working on it as no good results have come out so far.
A．have worked
B．had worked
C．have been working
D．had been working
答案
答案：D
考查时态。句意：在我加入他们之前，他们一直在这个项目上工作了将近一个星期。结合语境可知本句描述的在过去已经完成的正在进行的动作，故用过去完成进行时态，选D。