—What’s the matter with John? He has been sitting there for hours.
—A postcard from his father an attack of home-sickness in him.
A. took up
B. set off
C. brought in
D. built up
网友回答
A. took up
(答案→)B. set off
C. brought in
D. built up
解析：考查动词短语辨析。A占据，从事于，开始做；B引起，出发；引爆；C介绍，引进；赚钱；D建设，搭建；句意：—John怎么了？他坐在那里好几个小时了。—他爸爸的一张贺卡让他想家了。本句中的set off指引起。故B正确。