The old man was the only person on the spot helped him a series of facts as told
A. who, set up
B. who ,set down
C. which ,set out
D. that, set off
网友回答
A. who, set up
(答案→)B. who ,set down
C. which ,set out
D. that, set off
解析：考查定语从句和词组：句意：这个老人是唯一的在出事地点帮助他的记下一系列事实的人。第一空是定语从句的关系词，因为先行词是person，定语从句用who或that引导，第二空填set down记下，set up建立，set out出发，set off引发，引爆，出发，选B。