plane harmonic motion

例句：

1. 1. The pilot flew the plane to safety.
   飞行员驾驶飞机安全降落。
2. 2. He boarded the plane and took his seat.
   他登上飞机，找到了自己的座位。
3. 3. The plane landed safely after a long flight.
   经过长时间的飞行，飞机安全着陆。