题目

To us, it seems so natural to put up an umbrella to keep the water off when it rains. But actually the umbrella was not invented as protection against the rain. Its first use was as a shade against the sun!Nobody knows who first invented it, but the umbrella was used in very ancient times. Probably the first to use it were the Chinese in the 11th century BC.We know that the umbrella was used in ancient Egypt and Babylon as a sunshade. And there was a strange thing connected with its use: it became a symbol of honor. In the Far East in ancient times, the umbrella was allowed to be used only by 如图，作此图关于直线AB的轴对称图形．