问题补充：
They on the program for almost one week before I joined them, but still no good results so far.
A. had worked ; come out
B. have worked ; came out
C. had been working ; have come out
D. have been working ; have come out
答案：
A. had worked ; come out
B. have worked ; came out
(答案→)C. had been working ; have come out
D. have been working ; have come out
解析：可联系答.案.网客服索取。
