把一小块金属钠放入下列溶液中，既能产生气体又会出现白色沉淀的是[ ]
A．稀硫酸
B．氢氧化钾稀溶液
C．硫酸铜溶液
D．氯化镁溶液
答案：D
I don't know what decisions ______ at the conference as John hasn't reported to me yet.
A．wouldmake
B．willmake
C．aremade
D．weremade
欲配制100mL 1.0 mol/L Na2SO4溶液，正确的方法是( )
①将14.2 g Na2SO4溶于100mL水中；② 将32.2g Na2SO4·10H2O溶于少量水中，再用水稀释至100 mL；③ 将20 mL 5.0 mol/L Na2SO4溶液用水稀释至100 mL
A．①②
B．②③
C．①③
D．①②③
