A:Na2S溶液使酚酞试液变红:S2-+2H2O2OH-+ H2S
B:在醋酸溶液中加入Na2CO3溶液:CO32-+2H+=CO2↑+H2O
C:NH4HCO3溶液与过量NaOH溶液混合:NH4++OH-=NH3•H2O
D:用小苏打治疗胃酸(含盐酸)过多:HCO3-+H+= CO2↑+H2O
Before,I didn't like winter.Now,I love to play in the snow.
从车站向东走400米,再向北走500米到小红家;从车站向北走500米,再向西走200米到小强家,则( )
抛物线y=ax(x﹣2)经过坐标原点O,与x轴相交于另外一点A,顶点B在直线y=x上;