题目

—Why didn’t you stop the ball? —________ I could catch it, a boy from Class Three suddenly appeared and caught it.A. UntilB. WhenC. AfterD. Before 答案：D如图，已知圆，经过椭圆（a＞b＞0）的右焦点F及上顶点B，过椭圆外一点（m，0）（m＞a）倾斜角为的直线1交椭圆于C，D两点（1）求椭圆的方程（2）若右焦点F在以线段CD为直径的圆E的内部，求m的取值范围．