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

下列哪一项是意外发生后，实时到达现场作调查，第一件要办的事?

A.消除或稳定残存在现场的危险，以免再发生意外 

B.寻找各方目击证人，尽可能实时录取口供 

C.分析及记录有关证物