问题
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
B:had worked; were still working
C:have been working; have worked
D:have worked; are still working
正确答案是：
