题目

阅读理解 阅读下列材料，根据其内容选择最佳答案。                                    CompassIt was a great gift to the world from ancient China. Before it was invented, sailors had to depend on the stars to find direction. After it was invented, the oceans were open to travel. And many new discoveries were made with the help of it.GunpowerIt was one of the greatest inventions. It is said that in the 3rd century a Chinese man wrote about how to make it. At lirst, it was used for making fireworks. At the end of the Tang Dynasty, people bega在皮鞋擦过鞋油，还要用鞋刷或软布反复擦几下，越擦越亮，这是由于（　　）A．反复擦可增加漫反射效果B．反复擦可使鞋油填平皮革表面的凹坑，增加表面光滑程度，增加镜面反射效果C．鞋油反光性能比皮革好，反复擦可使鞋油均匀分布，增加漫反射效果D．鞋油的颜色比皮革鲜艳，可增加镜面反射效果