Suddenly, he felt the light touch of a fin. The little blue fish was back!

突然间，一只小小的鳍轻轻碰他，原来是蓝色小鱼回来了！

The pet has a fin. The net has a rip.

• 宠物有鳍。网有裂口。

Without a fin, a shark can no longer swim and slowly dies.

失去了鱼鳍，鲨鱼无法游泳就会慢慢死亡。

To adapt to an aquatic lifestyle, Ichthyosaurs evolved paddle like front and hind limbs as well as a fin tail.

为了适应水生生活方式，鱼龙进化出了像桨一样的前后肢以及鳍状尾巴。

Do you see the fins of the gold-fish? It has two breast-fins, two belly-fins, a back-fin, a tail-fin, and a fin on its under side near the tail.

你看见金鱼的鱼鳍了吗? 金鱼有两个胸鳍、两个腹鳍、一个背鳍、一个尾鳍, 还有尾巴附近的一个臀鳍。

A third option is that it's all basically just a  game, and that the orcas are having fun taking a chunk of the boat that looks like a fin.

第三种选择是，这基本上只是一场游戏，逆戟鲸正在享受着船上看起来像鱼鳍的一块块的乐趣。

SABRINA IMBLER: The scientists marveled at  the bream's collective action, approaching and mobbing a predator such as a sand striker invites  real danger: losing a fin, a patch of scales, even dying.

萨布丽娜·因布勒：科学家们对鳊鱼的集体行动感到惊讶，它们接近并围攻沙鳊这样的捕食者会带来真正的危险：失去鳍、一片鳞片，甚至死亡。