同学们，你们喜欢观察身边的事物吗?无论是雄伟壮丽的高楼、大桥，还是伴随身边的生活用品，对顶角几乎无处不在．但不知你们是否注意到，生活中的大多数对顶角，无论角的大小是否固定，其位置始终成对顶角．但也有些对顶角，却来也匆匆，去也匆匆，不给我们留下片刻欣赏的机会． Students, do you like to observe things around you? Whether it’s a majestic high-rise building, a bridge, or the daily necessities around you, it’s almost everywhere. But I do not know if you have noticed that most of the life in the top corner, regardless of the size of the corner is fixed, its position is always a pair of top corners. But there are also some of the top corners, but they come in a hurry, and they go in a hurry, leaving us no chance to appreciate for a moment.