The incident a chain of events which resulted in the outbreak of the World War I.A. set o

问题补充：

The incident a chain of events which resulted in the outbreak of the World War I.

A. set out

B. set off

C .set about

D. set in

答案：

解析：考查短语辨析，set out出发，set off动身，引起，爆发，set about着手工作，set in开始，到来，句意：这件事引起了一连串的事件，导致了第一次世界大战的爆发。所以选B。