burr fin

例句：

1. 1. The fish was swimming with its burr fin out of the water.
   那条鱼带着它的鱼雷尾在水里游。
2. 2. The captain used his rudder to steer the ship through the storm.
   船长用他的舵来引导船穿过暴风雨。
3. 3.The pilot had to use his tail to avoid hitting a rock on the riverbank.
   飞行员不得不用尾巴避开河岸上的一块石头。