我国北方冬天比较寒冷，许多家庭安装了一种利用电来取暖的床—“韩式电热炕”．其工作电路可简化为如图所示，其中K为保护开关，平常处于闭合状态，当温度超过某一警戒温度时自动断开，扇形导体S为旋转型选档开关，可绕0点旋转，每次都和相邻的两触点同时接触，从而实现关、低、中、高四个档位的转换（档位顺序未知，电功率越大档位越高）．小明在家里利用所学的物理知识来测量该电热炕的电功率．他先关闭家里其它所有的用电器，然后将S旋转到与触点1、2连接，观察发现家里标有“3000r/（kW•h）”的电能表的转盘在1min内刚好转了20转．已知R₁和R₂是发热电阻，R₂的阻值是R₁的2倍，其它电阻忽略不计，小明家电压恒为220V．完成下列问题：

斯塔夫里阿诺斯在《全球通史》中写道：“旧制度所显示的破产导致旧制度的变革。第一个变革是解放农奴……这是俄国历史上的一个重大转折点……工厂工人的数目从1865年的381000人上升到1890年的1620000人……”材料显示这次改革（　　）

    I think 1likes dogs. Dogs are our friends. My friend Tomson likes dogs very2 . He has a big dog. 3name is Bobo. He's bright(聪明的). Every Saturday aftemoon Tomson takes Bobo for a long walk in the street. Sometimes Tomson takes Bobo to the park. Tomson4the frisby and Bobo catches it in the air. Bobo can open the door and close the door. When Tomson goes to school, Bobo stands in5of the door and waits6Tomson coming. When he sees Tomson, he7 the door and catches his bag. What a bright dog!

    I like Bobo. I often go to Tomson's home to play8 him. I often give Bobo  9  to eat. I want to have a dog, too.

完形填空

    The 2013 Talent Show in our school was a night to remember! It was a great1Students, parents and teachers2, sang and played instruments. There were more than thirty3. Our English teacher Jason Cruise4an English song. He won the prize 5 the best performer. 6a reporter from our school magazine interviewed him, he said that singing was7important to him. The prize for the funniest act8to Paul Black, because he danced like a drunken (喝醉的) man without music. And his classmates said he was the9boy in the class.

    Many thanks to the parent and the student volunteers. They made this10show possible. Many thanks to all of the people who helped.