题目

My washing machine ________ this week, so I have to wash my clothes by hand. A . was repaired B . is repaired C . is being repaired D . has been repaired 答案：C已知三角形ABC三顶点坐标分别为A(5，2)，B(3，4)，C(-1，-4)，则这个三角形是（　） A．锐角三角形　　    B．直角三角形 C．等腰直角三角形　　　　    D．钝角三角形