如图所示电路，开关S原来是闭合的，当R₁、R₂的滑片刚好处于各自的中点位置时，悬在空气平行板电容器C两水平极板间的带电尘埃P恰好处于静止状态。要使尘埃P向下加速运动，下列方法中可行的是 （　　　）  
 

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中单词的正确形式填空
    Do you know how to be a top student? Top students are decided by a new way now. New rules for middle school students ____ (come) out in March. The best students should not only have good grades. You'll be a top student ____  you follow the new rules.____  (one), you need to be honest. You should never copy others’ homework. Second, good students love animals and care____ other people. They try to do something to protect animals, too. Are you one of them? Third, you should learn that teamwork____  important. So be friendly to the people you are with and it can make your team stronger.

设A=0.09×8+0.10×8+0.11×8+…+0.28×8，则A的整数部分是____ ．