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

Download及Load完补丁程序后，次时补丁文件的后缀名是哪一种（）

A.exe

B.tmp

C.pch

D.swl