A:working, stopping
B:to work, stopping
C:working, to sto
D:to work, to sto
在平面直角坐标系xOy中,已知椭圆 x2a2+y2b2 =l (a>b>0)的焦距为2,离心率为 22 ,椭圆的右顶点为A.
假如没有重力,下列哪些现象不会发生( )