胸鳍

例句：

1. 1. The fish swims with its long, flexible tail and two powerful pectoral fins.
   这条鱼用它那长而灵活的尾巴和两只有力的胸鳍游动。
2. 2. In some species of fish, the pectoral fins are modified into wings.
   在某些鱼类中，胸鳍被改造成了翅膀。
3. 3.The scientist observed the fish's movements closely to study its swimming technique.
   这位科学家仔细观察了这条鱼的动作，以研究其游泳技巧。