问题补充:
By the time he got up, I for two hours in the factory.
A. have worked
B. worked
C. was working
D. had been working
答案:
A. have worked
B. worked
C. was working
(答案→)D. had been working
解析:考查时态。本题的关键词是by,该词通常与完成时连用,句意:到他起床的时候,我已经在工厂里工作了两个小时了。他起床使用了过去时got up,我工作两个小时是在此之前,故使用了过去完成进行时的时态。故D正确。