题目

在平面直角坐标系中，为坐标原点，为单位圆上一点，以轴为始边，为终边的角为，，若将绕点顺时针旋转至，则点的坐标为（    ） A.    B.    C.   D. 答案：BWilliam found it increasingly difficult to read, for his eyesight was beginning to __________.A. disappear B. fall C. fail D. damage