—You were out when I dropped in at your house yesterday.
—Oh, I for a friend from Beijing at the railway station.
A. was waiting
B. had waited
C. am waiting
D. have waited
网友回答
(答案→)A. was waiting
B. had waited
C. am waiting
D. have waited
解析：根据上句中的时间状语的提示可知谓语动词是指过去某时正在发生的事情，因此用过去进行时态，故答案为 A。