题目

下列物质中，导电能力最强的是(    ) A.加热后的NH4HCO3                        B.KNO3溶于水C.无水乙醇                                       D.CuSO4·5H2O 答案：B  解析：A.NH4HCO3受热分解，NH4HCO3NH3↑+H2O+CO2，不能熔融电离。C.乙醇为非电解质。D.CuSO4·5H2O中H2O为结晶水，不能使CuSO4电离。--- ________ do you go to see movies? --- Twice a month. [　　] A．How oftenB．How many C．WhenD．How