高钠血症是指血清钠超过()
A.135mmol/L
B.145mmol/L
C.155mmol/L
D.165mmol/L
E.175mmol/L
参考答案:B
零除以任何有理数都等于0. ______(填“正确”或“错误”)
牙本质中的无机盐按重量和体积算各占多少?()
A.70%,45%
B.75%,35%
C.80%,30%
D.90%,50%
E.98%,20%