n.直升机
The worst thing that can happen to a helo, aside from outright being destroyed, is for it to have an engine failure. 对于直升机来说，除直接摧毁外最坏的情况就是发动机失效。
n.单身汉；学士
士人
n.未婚女子
n.职权的等级；阶层；梯队；梯次编队
v.排成梯形
n.独身；独身生活
