The light in his office is out. He left for home.
A. must have
B. must have been
C. should have
D. should have been
网友回答
(答案→)A. must have
B. must have been
C. should have
D. should have been
解析：句意：办公室的灯灭了，他一定已经离开回家了。从The light in his office is out.可知是对过去的肯定的推测，用must have done“过去一定做了”，should have done“过去本应该做而没有做”，所以选A。