blade fin

例句：

1. 1. The chef used a blade tocut the vegetables.
   厨师用刀片切蔬菜。
2. 2.The fisherman used his blade finto catch the fish.
   渔夫用他的鱼鳍来捕鱼。
3. 3. The boat was propelled by its blade fin.
   船是由它的鱼鳍推进的。