在潜水作业的条件下，潜水员体内矿物质代谢受到较明显影响的是（）
A.钙
B.铁
C.钾
D.钠
E.锌
参考答案：C
Bob’s salary is three times ______, so John admires Bob very much.
A．as high as that of John
B．as bigger as that of John
C．as high as John
D．as much as John
由2K×1bit的芯片组成容量为4K×8bit的存储器需要（）个存储芯片。
A.2
B.8
C.32
D.16
