已知方程|2a+3b+1|+(3a-b-1)2=0,求a2+2ab+b2的值.
略
某人使用针管注射毒品被查获,其注射针管属()。
A.违禁品
B.作案工具
C.合法财物
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