题干
Faced with the crisis(危机), the government _________ calm and took timely measures.
A：grew
B：appeared
C：became
D：stayed
答案(点此获取答案解析）
D
的左右顶点，若在椭圆上存在异于A1、A2的点
，使得
，其中O为坐标原点，则椭圆的离心率
的取值范围是
