等渗性缺水纠正后应注意补（）。
A.钙
B.镁
C.钠
D.钾
E.氯
参考答案：D
--- Will you go to the party? --- No, even though ___ to.
A．inviting
B．being invited
C．invited
D．having been invited
二次函数y=-x2+2x+3的图象与x轴交于A、B两点，P为它的顶点，则S△PAB=______．
