四个数，每次选出三个数算出它们的平均数，用这种方法计算了四次，分别得到四个数：86，92，100，106．那么原来这四个数的平均数是（　　）

如图所示，电磁铁左侧的甲为条形磁铁，右侧的乙为软铁棒，A端是电源的正极.下列判断中正确的是（   ）

根据高中所学的化学反应原理解答下面的问题：

       My now 7-year-old grandson, who lives 100 miles away, has kept my phone number in his mind since he was 4. Since then, he has been  1 me every night before he goes to bed to tell me about his day or just to say “Good night, Grandma.”
    He also often calls me at other times during the day just to  2  a happy or sad moment. Many times he's playing a basketball with one hand, or laughing with a friend about something that I  3quite understand, or crying about something he may or may not want to talk about while I'm on the other end of the phone. I just listen and empathize (同情) or laugh with him—just share his current (当前的)  4 . I always let him control the  5  , and the time he's on the phone with me. Many times I just listen to him play, or play games we've made up together that we can play over the  6 .   
      The only time I take control of the 7  is when he's ready to say goodbye at night. Often there are four special   8  I say to him every night. One night I thought maybe he was tired to hear those, so I didn't say them. He  9 called me back and told me that I forgot to say those sentences! I haven’t missed saying them since then!
      My friends all know that he is the most important for me.  10  I'm in church(教堂), or some place where I really can't take his call, I always politely excuse myself and talk to him, even if it's just for a minute to tell him I'll call him back in a few minutes.
He knows that he takes first place in my heart.

感恩:生命中的心灵之花
①“滴水之恩，涌泉相报”，这是一句并不深奥的话，可是真正理解并做到的人能有多少呢？生活中关于翻脸不认人或以怨报德的“白眼狼”的传说，每每有所耳闻，令人徒然唏嘘不已。于是，说某某人“不知好歹”、“良心被狗吃了”的斥责与评论，就在口头传播中无形地为某人画了像，其人品足以让他失去亲友的关爱与尊重，让他的事业和生活面临很多困难。
②现在谈论感恩这个话题，具有相当广泛的社会意义。一方面，不少成年人被“金钱万能”所左右，自私自利，只认钱不认人，只讲索取不讲回报，淳朴之风、感恩之心日渐式微；另一方面，独生子女过分受宠，衣来伸手、饭来张口，不知体贴和心疼父母，虽然能背诵“谁知盘中餐，粒粒皆辛苦”、“慈母手中线，游子身上衣”这样的古诗，可是自我中心意识在家人的不断纵容中强化。因此，感恩教育要将学校教育、社会教育、家庭教育结合起来，决不是仅仅靠书本知识就能奏效的。在价值多元化的状况下，如何弘扬感恩美德，培育青少年感恩的人格并自觉形成感恩的伦理观，这是构建和谐社会的深层次内容之一。  
③感恩不是浅层次的庸俗的“投桃报李”，更不是表面的甜言蜜语。它是人类在生命延续过程中的心灵之花，散发出沁人心脾的芳香；它是人性中真善美的乐章，将爱心传递，使人的理智与情感本身具有了审美的意义；它是为人父母者的幸福与欣慰，是为人子女者的本分与情操，是人与人之间的虔诚。假如没有感恩，人类的繁衍与生存就成为纯粹生物学意义上的基因复制，陷入鸡生蛋、蛋生鸡的简单怪圈。这样，就诞生不了朱自清的美文《背影》，就品味不了朱德感人肺腑的《母亲的回忆》，也欣赏不了童话般的校园歌曲《外婆的澎湖湾》。
④由此看来，感恩实在是不用勉强的，它是我们人生的必修课，更是一个高尚的人应该具有的境界与素质。
⑤父母养育子女，并非“施恩图报”，父爱母爱如山高比海深。那么，子女对父母的感恩就是绿叶对根的情意，孝敬在言行上，也在心灵深处。有智者说，看一个人品行如何首先就看他是否孝敬父母，一个人如果连父母都不孝敬，那就既不能做朋友，也不能扛重任。诚哉斯言！
⑥感恩，就是孝敬父母，就是怀念恩师，就是报效祖国，就是对于成长的一种回馈。感恩，将使我们的心灵永远温暖如春 。