A:Nn
B:n
C: Nn
D: Nn +1
Linda needn't________her parents any more—she could be entirely independent by working as a nurse.
如图所示,电源电压不变.闭合开关S,滑片P分别在A、B两点时,电压表V1的示数比是4:3;当P在A点时,电压表V1、V2示数比为1:2.求:
市场上销售的食盐种类有加钙盐、加碘盐,这里的“钙”、“碘”指的是( )