题目

 What worries me most is that my daughter________most of her spare time ________playing games on the computer.A.concentrates；on B．concentrates；in C．focuses；to D．focuses；in 答案：A11．根据光的反射定律在图中用光路作图的办法画出点光源A发出的光经过平面镜反射后照亮墙面M的范围．（请保留作图痕迹）