问题
选择题
| 如图所示，用控制变量法可以研究影响平行板电容器电容的因素．设两极板正对面积为S，极板间的距离为d，静电计指针偏角为θ（θ与电容器两板间的电压U成正比）．实验中，极板所带电荷量不变，若（ ） A．保持d不变，减小S，则θ变小 B．保持d不变，减小S，则θ不变 C．保持S不变，增大d，则θ变小 D．保持S不变，增大d，则θ变大  |
答案
答案：D
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| 如图所示，用控制变量法可以研究影响平行板电容器电容的因素．设两极板正对面积为S，极板间的距离为d，静电计指针偏角为θ（θ与电容器两板间的电压U成正比）．实验中，极板所带电荷量不变，若（ ） A．保持d不变，减小S，则θ变小 B．保持d不变，减小S，则θ不变 C．保持S不变，增大d，则θ变小 D．保持S不变，增大d，则θ变大 |
答案：D
“ Are you too stupid to do anything right？”These words—said by a woman to a little boy who was obviously her son—were spoken 21 he had walked away from her．They boy returned, his eyes down-cast. Not a 22 moment, perhaps, 23 small moments sometimes last a very long time．And a few words—though they mean 24 at the time to the people who say them—can have great 25 . I recently heard a story from a man named Malcolm Dalkoff．For the last 24 years he has been a professional 26 ．Here is what he told me: As a boy in Rock Island, Dalkoff was terribly 27 ．He had few 28 and no self-confidence．One day, his English teacher, Ruth Brach, gave the class an assignment（作业）．The students had been reading To Kill a Mockingbird．Now t  hey were to write their own chapter that would 29 the last chapter of the novel.Dalkoff wrote his chapter and turned it 30 ．Today he can not recall anything 31 about the chapter he wrote, or what 32 Mrs．Branch gave him．What he does remember is the four words Mrs．Brach wrote in margin（空白处）of the paper：“This is 33 writing.” Four words．They 34 his life. “ 35 I read those words, I had no idea of who I was or 36 I was going to be.”he said.“After reading her note, I went home and wrote a short story, something I had always been 37 of doing but never believed I could do.” Over the rest of that year in school, he wrote many short stories and always brought them to school for Mrs．Brach to evaluate．She was 38 , tough and honest.“She was just what I 39 .”Dalkoff said. His confidence 40 ．Dalkoff believes that none of this would have happened if that woman had not written those four words in the margin of his paper.
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