C:C3H6和C5H10
A:C3H4和C5H8
B:C2H5Cl和C3H6Cl2
D:C3H8和C5H12
已知△ABC的周长等于18,B、C两点坐标分别为(0,4),(0,﹣4),求A点的轨迹方程.
We only have _______ shower.