维持细胞外液渗透压的重要离子是( )。
A．K+B．Na+C．Mg2+D．H+E．Ca2+
参考答案：B
解析：[知识点] 体液的平衡及调节
Only when I was told the news ___ that he himself was the great hero.
A．I knew
B．I did know
C．did I know
D．did I knew
准时生产方式中的诸多手段都是围绕____而展开的。
