问题补充：
---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
答案：
A. took up
(答案→)B. set off
C. brought in
D. built up
解析：句意：---John怎么啦？他好几个小时坐在那里。---他父亲的一张卡片引起了他的思乡病。set off引起，出发；take up占据；build up逐步建立，增强。故选B。
