题目

____ that saw the trade between the two countries reach its highest point.         A．During the 1980’s     B．That it was in the 1980’s         C．It was the 1980’s      D．It was in the 1980’s 答案：C动圆C与定圆C1：（x+3）2+y2=32内切，与定圆C2：（x-3）2+y2=8外切，A点坐标为（0，）．（1）求动圆C的圆心C的轨迹方程和离心率；（2）若轨迹C上的两点P，Q满足，求|PQ|的值．