Electrical conductivity（）
A.电导率
B.载流子数
C.载流子迁移率
参考答案：A
Would you like ___ knife and fork, or would you rather use __ chopsticks, sir?
A．the, the
B．a /
C．/, the
D．/, /
我国成人铜的适宜摄入量（AI）为（）
A.0.2mg/d
B.2mg/d
C.0.5mg/d
D.5mg/d
E.50mg/d
