中原工学院 /
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
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
参考答案：
佳题速递：