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：词组辨析题。A. brought up 养育 B. looked up 查阅 C. picked up学会 D. set up 设立句意：塞姆通过看别人操作学会了许多电脑知识。 根据语境选C
