-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：短语辨析。A占据，从事于，开始做；B引起，使…发生；C介绍，引进，赚钱；D逐步建立；句意：—John怎么了？他坐在那里好几个小时了。—爸爸给他寄的一张明信片让他开始想家了。本题中的set off指引起的意思。故B正确。