During the summer holiday, my grandparents went to China. First they flew to Beijing from London. Then they went to Guangzhou by train.

    When they wentto my home, I wanted to help my grandpa carry his heavy bag, but he did himself.  They bought many presents for us.  I got a dress.  My brother got a toy plane. They brought many dried fruits for us, which they grew by themselves. My grandparents are farmers. They are hard-working people.

关于烷烃性质的叙述中，不正确的是（     ）

如图所示，某电子电路的输入端输入电流既有直流成分，又有交流低频成分和交流高频成分．若通过该电路只把交流的低频成分输送到下一级，那么关于该电路中各器件的作用，下列说法中正确的有（   ）

“锦绣河山收拾好，万民尽作主人翁。”这说明（    ）

①我国是工人阶级领导的、以工农联盟为基础的人民民主专政的社会主义国家   ②在我国，人民是国家的主人

③全民进入小康社会后，社会上将不存在敌对分子和敌对势力                               ④人民作为国家的主人，会有军队维护国家的长治久安