--- Why was she unhappy yesterday ?
--- A call from home an attack of homesickness.
A. set off
B. set out
C. set about
D. set down
网友回答
(答案→)A. set off
B. set out
C. set about
D. set down
解析：考查词组：A. set off出发，引发，引爆B. set out出发，开始C. set about开始D. set down记下，句意：--昨天她2为什么难过？--家里的电话引起她想家了。选A。