题目

质量的钠、镁、铝分别与足量的盐酸反应，产生H2的质量由大到小的排列顺序正确的是A、AL、Mg、Na       B、Mg、AL、Na      C、Na、Mg、AL     D、Na、AL、Mg 答案：A---How often does she have dancing classes?-_________.A. On Saturday afternoonB. At 9 o’clockC. Once a week