问题
选择题
They ______ on the program for almost one week before I joined them, and now we _____on 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
答案：A
此题的时间参照点是before I joined them,，所以第一个空应该用过去完成进行时，第二个空根据时间now用现在进行时。
【标签】动词时态