问题补充:
Sam some knowledge of the computer just by watching others working on it.
A. brought up
B. looked up
C. picked up
D. set up
答案:
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。