fin ray

例句：

1. 1. The fish swam gracefully with its long fin.
   这条鱼游动时长着漂亮的鳍。
2. 2. The dolphin has a unique fin shape that helps it swim efficiently.
   海豚有独特的鳍形，这有助于它高效游泳。
3. 3. The whale's fin is used to propel itself through the water.
   鲸鱼的鳍用来推动自己在水里前进。