题目

 ---Do you still remember ________when the teacher came in? ---Of course, I was doing my math exercise.A. what you were doing              B. what you are doing   C. what were you doing              D. what are you doing 答案：A已知双曲线 (a＞0,b＞0)的左右焦点分别为F1、F2，点P在双曲线的右且 ∣PF1∣=4∣PF2∣,则此双曲线的离心率e的最大值为           （  ） A．              B．               C．２                D．