形形色色的年轮年轮是树木在树干的横切面上所呈现出的同心圆的轮层。随着科技的发展，人们又获悉，许多动物甚至无生命物质也有记录自身寿命的年轮。大自然的周期性更迭，在许多鱼类鳞片上留下了清晰的痕迹：那鳞片上大圆与小圆间的明显分界线，是在标明鱼类的年轮。不过... Various types of annual rings The annual rings are concentric circles of trees that appear on the cross-section of the tree trunk. With the development of science and technology, people have learned that many animals, even lifeless substances, also have their own life-ring. The cyclical nature of nature has left a clear mark on many fish scales: the clear dividing line between the great circle and the small circle on the scale, marked by the annual rings of fish. but...