题目

What does you brother do?             A. He works very hard.                                       B. He is outgoing and friendly.             C. He is a sales assistant.                                     D. He is tall with curly hair. 答案：C（2011•甘肃模拟）已知点F1、F2为椭圆x225+y216=1的左右焦点，过F1的直线l交该椭圆于A（x1，y1）B（x2，y2）两点，△ABF2的内切圆的周长为π，则|y1-y2|的值是（　　）A．53B．103C．203D．53