A round moon in the sky an attack of homesickness to Li Bai and then came the poem, A Tranquil Night.
A. set in
B. set out
C. set about
D. set off
网友回答
A. set in
B. set out
C. set about
(答案→)D. set off
解析：考查动词短语：A. set in嵌入，B. set out出发，动身，C. set about出发，动身，D. set off引发，引起，引爆，出发，句意：天空的一轮圆月引发李白的思乡情绪，然后就写了《静夜思》这首诗。