题目

阅读短文，并根据短文后面的要求答题。（注意字数要求） Do you want to work with people or animals or machines or tools? Do you want to work indoors or outdoors, directly serve people in need or serve people behind the scenes? These are the typical questions that a volunteer service agency would ask． Every year, thousands and thousands of people in the west offer volunteer services．Volunteering greatly strengthens the community partly because it helps the old, the young, the weak, the sick, the disabled and the injured to overcome difficulties． Volunteers usually h如图，在平面直角坐标系中，点A的坐标为（1，0），以线段OA为边在第四象限内作等边三角形AOB，点C为x正半轴上一动点（OC＞1），连接BC，以线段BC为边在第四象限内作等边△CBD，连接DA并延长，交y轴于点E．①△OBC与△ABD全等吗？判断并证明你的结论；②当点C运动到什么位置时，以A，E，C为顶点的三角形是等腰三角形？