题目

While staying in Scotland alone,         A loneliness was always around me      B many interesting places were visited.C I was a bit homesick                       D my friends in China encouraged me a lot 答案：C求以直线x+2=0为准线，离心率为，恒过定点M(1，0)的椭圆长轴长的最大值，并求长轴最长时的椭圆的标准方程．