题目

 Be careful when you cross the road in rush hours so as to avoidby a car. A. being knocked down               B. knocking down C. to be knocked down               D. to knock down 答案：A1．不能实现如图所示的变化的是（　　）  选项XYZ箭头上所标数字的反应条件ACaOCa（OH）2CaCO3①常温遇水BAlCl3NaAlO2Al（OH）3②通入CO2CNa2CO3NaOHNaHCO3④过量Ca（OH）2溶液DCl2Ca（ClO）2HClO③加浓盐酸A．AB．BC．CD．D