如图所示，a、b是镜前一点光源S发出的光线经平面镜反射后的两条反射光线，请根据平面镜成像规律在图中标出像点S，和点光源S的位置，并画出对应的入射光线．

华——____——____   匈——____——____

哥——____——____   成——____——____

    There are forty-eight students in our class. There are twenty-three boys and twenty-five girls. Some students live near the school, and some others live very far from the school. About half of the students come to school by bike. They often get to school at a quarter to seven. About ten students often come to school by bus. They often go to school very early, too. Another ten students come to school on foot. Their homes are near the school, but they are often late for school, because they get up very late.

当今世界，美国是唯一的超级大国，俄罗斯拥有庞大的军事力量，日本拥有强大的经济力量，中国是世界上最大的发展中国家，这反映出 （   ）