企源知识库

(   ) we could find no sign of the man and the search had to be terminated.
A、Possibly
B、Sensibly
C、Regrettably
D、Doubtfully
【正确答案】：C
【题目解析】：Possibly也许，大概；Sensibly明显地；Regrettably遗憾地；Doubtfully怀疑地。句意：遗憾的是，我们没有找到那个人的任何踪迹，搜寻工作不得不终止。