They don't know _____their parents are.[ ]
A. that
B. what
C. why
D. which
答案：B
将少量金属钠分别投入下列物质的水溶液中，反应后溶液质量减轻的是[ ]
A. HCl
B. K2SO4
C. NaOH
D. CuSO4
一个汉字的国标码需用( )。
A．1个字节B．2个字节C．4个字节D．8个字节
