⑴把天平放在水平桌面上，将____移到标尺左端的零刻线处后，发现天平横梁左高右低，应将右侧的平衡螺母向____（选填“左”或“右”）调节，使天平平衡；

⑵用调节好的天平测量空烧杯的质最m₁：

⑶把配制好的盐水倒入量筒中，测量盐水体积V，如图甲所示；

⑷把量筒中的盐水全部倒入烧杯中，测量烧杯和盐水的总质量m₂，如图乙所示．请根据图中数据，帮小华同学把下表填写完整：

⑸以上方法测出的盐水密度值比真实值____（选填“偏大”或“偏小”）；

⑹小华同学发现混杂在种子中的小石块也同饱满的种子一起沉入了盐水底部，她想知道石块的密度有多大，就选了一块大小合适且与其材质相同的石块，巧妙利用图乙所示的天平状态，按以下的步骤测出了石块的密度．

①用细线栓着石块浸没在盐水中 （石块未接触烧杯底且盐水未溢出），天平读数增大了△m₁；

②将石块缓慢沉入烧杯底部，放开细线，天平读数又增大了△m₂：

③石块密度的表达式ρ_石（用△m₁、△m₂及盐水密度ρ表示）____．

    One little miracle (奇迹) has been happening to me recently， and it gives me a special joy.

    A few months ago， I was telling my daughter， Sally， some stories about my mother. My daughter was so young when my mother died that she doesn't remember her well. I told her all I could remember， like how wonderful my mother was and how much she meant to me.

    One day， Sally was sad because her grandmother was in heaven (天堂) and she couldn't

    see her. I explained that though her grandmother was dead， now she was still watching over us and could send us something to let us know she was there. She could be anywhere， even riding invisibly (看不见地) on the back of a butterfly (蝴蝶). Just after I said this， a butterfly flew down right by us， and we laughed happily.

    Now many people would say it was just luck that the butterfly flew down at that time. A funny thing， however， has happened since then. Every time I go out in any type of weather I see butterflies. Very often they fly right by my face to get my attention. I always say hi to Mom，send her my love， and thank God for little miracles.

    Everyone is always looking for some big miracles to come out and save them when they are in trouble， but they don't notice the little miracles that happen every day right in front of their eyes. I know what they really are， however. For me little miracles are the best kind. So many little miracles happen around me all the time that I know they are not just luck.

根据短文内容，选择最佳选项。

材料一：中国自古代封建贵族社会移转而成四民社会，远溯自孔子儒家，迄于清末。两千四百年，士之一阶层，进于上，则干济政治。退于下，则主持教育，鼓舞风气。在上为士大夫，在下为士君子，于人伦修养中产出学术，再由学术领导政治。广土众民，永保其绵延广大统一之景运，而亦永不走上帝国主义资本主义之道路，始终有一种传统的文化精神为之主宰。此非深明于中国所特有的四民社会之组织与其运用，则甚难明白其所以然。

——钱穆《国史新论》

材料二：1902年底，梁启超在《新民说》中率先使用上等、中等、下等社会的概……其主旨是：上层已朽，下层尚愚，须由中等社会开通和引导下层社会去改造上层社会。这种源于中国历来上流与下流社会分别及近代欧洲等级制的认识，与当时意大利社会学家帕累托提出的精英分层理论相当近似，象征着中国趋新知识人士的自觉。

——桑兵《拒俄运动与中等社会的自觉》