–Why do you know so much detail about the accident?
--I a walk nearby when it happened.
A. had
B. had had
C. was having
D. would have
网友回答
A. had
B. had had
(答案→)C. was having
D. would have
解析：考查时态。根据句意 “当事故发生的时候，我正在附近散步”可知用过去进行时，表示过去正在发生的事情。句意：——你为什么知道这么多这起事故的细节？——当事故发生的时候，我正在附近散步。故C正确。