A:寒潮
B:台风
C:干旱
D:洪涝
已知不等式组x>2x>m的解集是x>2,则m的取值范围是( )
John ________ his grandma every day when she was in hospital.
如图所示,质量为m、带电量为﹣q的液滴从h高处自由下落,穿过A板的小孔进入匀强电场,到达B板时的速度刚好为零.设板间距离为d,不计阻力,则UAB=____,正极板是____.(空气阻力忽略不计)