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问题 问答题

下列推理是否正确为什么
一个人只有刻苦学习而又方法得当，他才会学有所成；小王学无所成；所以，小王或者未刻苦学习，或者方法不得当。

答案

参考答案：(1)这是一个必要条件假言推理，其推理形式不正确。
(2)它违反了必要条件假言推理“否定后件不能否定前件”的规则，犯了否定后件进而否定前件的逻辑错误。

完形填空

阅读下面短文，并按照题目要求用英语问答问题（请注意问题后词数要求）。

Some countries are better than others at looking after the environment. In Europe, Germany（德国）and northem European countries work very hard to improve the environment. The people in Germany put their rubbish into different bags-paper in one bag, plastic in laws that do not allow people to burn too much coal. In the 1970s ,as people learned more about environmental problems, the “Green” movement（运动）began and soon spread all over Europe. The “Green ”movement tries to get governments to protect the environment. It collects information about how industry is damaging（毁坏）the environment and tells newspapers. 

小题1:Which countries in Europe work very hard to improve the environment? (within 5 words)

                                                                                          

小题2:Who put rubbish into different bags? (within 4 words)

                                                                                           

小题3:Can the people in Germany burn too much coal? (within 1 words)

                                                                                           

小题4:When did the “Green “movement begin? (within 3 words)

                                                                                           

小题5:What does the “Green”movement try to do?  (within 6 words)

                                                                                           
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计算题

如图甲所示，静电除尘装置中有一长为L、宽为b、高为d的矩形通道，其前、后面板使用绝缘材料，上、下面板使用金属材料。图乙是装置的截面图，上、下两板与电压恒定的高压直流电源相连。质量为m、电荷量为-q、分布均匀的尘埃以水平速度v0进入矩形通道，当带负电的尘埃碰到下板后其所带电荷被中和，同时被收集。通过调整两板间距d可以改变收集效率η。当d=d0时，η为81%（即离下板0.81d0范围内的尘埃能够被收集）。不计尘埃的重力及尘埃之间的相互作用。

(1)求收集效率为100%时，两板间距的最大值dm；

(2)求收集效率η与两板间距d的函数关系；

(3)若单位体积内的尘埃数为n，求稳定的工作时单位时间下板收集的尘埃质量与两板间距d的函数关系，并绘出图线。

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