A：CaCO3与所有酸的反应都可表示为：CaCO3+2H+==Ca2++H2O+CO2↑
B：工业上用于刻蚀铜制印刷电路板的反应是：Fe3++Cu=Cu2++Fe2+
C：SiO2+CSi+ CO2↑是工业制取粗硅的反应
D：由反应SO2+Cl2+2H2O=H2SO4+2HCl可知，向新制氯水中通入SO2，溶液的pH会减小
Jane’s mum was ill yesterday, so she had to look her.
已知两条直线ax-y-2=0和a+2x-y+1=0互相垂直，则a等于( )
1元比10角少．
