请以“发现离不开用心观察”为题，写一篇文章。

说明：①要有自己的经历、体验和感悟，不得抄袭；②除诗歌、戏剧外，文体不限；③不少于600字；④请勿透露考生。

A

    Skin­diving is a new sport today. This sport takes you into a wonderful new world. It is like a visit to the moon. When you are under the water, it is easy for you to climb big rocks, because you are no longer heavy.

    Here, under the water, everything is blue and green. During the day, there is plenty of light. When fish swim nearby, you can catch them with your hands.

When you have tanks of oxygen on your back, you can stay in deep water for a long time. But you must be careful when you dive in deep water.

    To catch fish is one of the most interesting parts of this sport.

    What's more, there are more uses for skin­diving. You can clean ships without taking them out of water. You can get many things from the deep sea.

    Now you see that skin­diving is both useful and interesting.

①731部队相关遗址                ②奥斯维辛集中营遗址

③南京大屠杀惨案相关遗址        ④斯大林格勒战役照片

把几个数用大括号括起来，相邻两个数之间用逗号隔开，如：{1，2}，{1，4，7}，…，我们称之为集合，其中的每一个数称为该集合的元素，如果一个所有元素均为有理数的集合满足：当有理数x是集合的一个元素时，2016﹣x也必是这个集合的元素，这样的集合我们又称为黄金集合．例如{0，2016}就是一个黄金集合，