出租直升机

例句：

1. 1. The helicopter's rotor is the most critical part of its operation.
   直升机的旋翼是其运行最关键的部分。
2. 2. The rotor blades spin at high speeds to lift the aircraft off the ground.
   旋翼叶片以高速旋转，使飞机能够起飞。
3. 3. He was studying the mechanics of a helicopter's rotor when he fell asleep.
   他正在研究直升机旋翼的机械原理时睡着了。