题目

After too long on the Net, even a phone call can be a shock. My boyfriend's Liverpudlian accent suddenly becomes too difficult to understand after his clear words on screen; a secretary stone seems more rejecting than I'd imagined it would be. Time itself becomes fluidhours become minutes, and alternately seconds stretch into days. Weekends, once a highlight of my week, and now just two ordinary days.For the last three years, since I stopped working as a producer for Charlie Rose, I have done much of my work as a telecommuter. I submit（提交）articles and edit them via E-mail and commun若直线ax+by+c=0（a，b，c都是正数）与圆x2+y2=1相切，则以a，b，c为边长的三角形是（　　）A．锐角三角形B．直角三角形C．钝角三角形D．不能确定