Sam some knowledge of the puter just by watching others working on it.
A. brought up
B. looked up
C. picked up
D. set up
网友回答
A. brought up
B. looked up
(答案→)C. picked up
D. set up
解析：考查动词短语辨析。A抚养，抚育；呕吐；B查找；C捡起，用车接；无意中学会；D建立。成立；句意：Sam通过看别人玩电脑，无意中学会了电脑的知识。根据句意说明C正确。