放学了，你应该对老师说：

要测量物体所受重力的大小，可采用的仪器是（　　）

根据短文内容，选择正确答案。
D
    John sent for a doctor because his wife was ill. He called the doctor and made sure they would meet at five. He arrived at the doctor's at twenty to five. He thought. “It s a little bit earlier. I'll wait for a moment. It's good to keep the time. ”
    Then he stopped his car in front of the doctor's. He looked around and saw a noisy square not far from here. He went there and sat down on a chair to enjoy the last light of afternoon sun and make himself quiet. He saw some children playing and some women talking to each other happily.
    Suddenly he heard a girl crying. He came up to her and asked some questions. Then he knew she got lost. John tried to find out her address and took her home. The girl's parents were very thankful.
    Then John hurried to the doctor's. The doctor said angrily when he saw him “You're late. Why did you keep me waiting for 20 minutes?" John said nothing but one word "Sorry!”

1912年3月，南京临时政府令：“查前清官厅，视官之高下，有大人、老爷等名称，受之者增惭，施之者失体。……光复以后，闻中央地方各官厅，漫不加察，仍沿旧称，殊为共和政体之玷。”有研究者发现，同年6月《申报》载：“公堂会审之时，（被告）就口口声声以老爷、大人相称，裁判官亦直受不辞。”上述材料最宜作为下列哪一观点的论据？（    ）

现在中国有几个重要的节日是为了纪念新民主主义革命时期发生的重大事件，请联系现实生活中国家规定的纪念日，举出这几个节日的名称，并说明他们分别来源于哪一事件，以及这些事件的重要意义。