题目

国家之所以促进民族大团结，是因为：( ) ①民族团结是实现民族平等的政治基础   ②民族团结是各民族共同繁荣的物质保证  ③民族团结是维护社会稳定的前提，综合国力的重要标志之一  ④民族团结是经济发展和社会进步的保证，是国家统一的基础 A. ①②                                                           B.③④                         C.②③      D.①④ I failed again in the examination and only then _____ how much time I had wasted. A. I realized     B. I had realized      C. did I realize      D. had I realized