如图所示，半径为r且水平放置的光滑绝缘的环形管道内，有一个电荷量为e，质量为m的电子.此装置放在匀强磁场中，其磁感应强度随时间变化的关系式
（08年平遥中学理）设min{x1,x2,…，xn}表示x1,x2,…，xn中最小的一个．给出下列命题： ①min{x2,x-1}=x-1；②设a、b∈R+，有min{a, }≤；③设a、b∈R，a≠0，|a|
读甲乙丙丁四个国家的有关特征图（图3），回答6～7题。 6．与甲乙丙丁四国特征相符的是 A．印度、日本、澳大利亚、索马里
“首都十大道德模范”全市宣讲活动2009年7月26日结束，近万名首都市民现场与道德模范互动，感受“道德的力量”。首都文明办有关负责人表示，“首
Dear friends,Our high school is so wonderful. With the College Entrance Examination approaching, it won't be long 25.________ we graduate. Now, I have 26.m________ to share with all of you. Firstly
--- I hear that Hu Jintao will come to Nantong because the Sutong Bridge is open to traffic soon.--- Do you know _______?A．what will he talk aboutB．where will he give a talk C．how will he comeD
Dear Jenny， I’m sorry you’re sick and cant come to school this week．Let me tell you what you have on Monday next week． We have math at 8：00．How boring! Then we have English．That
