问题补充：
Theyon 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. had been working; are still working
B. had worked; were still working
C. have been working; have worked
D. have worked; are still working
解析：
试题分析:句意：我在加入他们之前，他们从事这个项目已经有几乎一周的时间了，现在我们仍然在做这个项目，因为到目前为止还没有好的结果出来。根据时间状语从句before I joined them可以判断主句应该用过去完成时，而后句中的now决定了第二个空的时态是现在时态，故答案选A。
