题目

 It was the third time that this question _______ at the meeting.    A. had come up       B. was come up        C. has come up       D. is come up 答案：A如图，已知A、B两点的坐标分别为（4，0）、（0，2），P是△AOB外接圆上的一点，且∠AOP=45°，反比例函数图象经过点P，则k的值为________．