题目

— John failed his final exam. — I’m not surprised at the news _______. ________, he is never seen busy with his lessons. A . at all, After all B . in all, After all C . above all, In all D . at all, In all 答案：A入射光线与镜面的夹角是40°，则入射光与反射光的夹角是______°；如果入射光垂直入射到镜面上，那么反射角是_______°