1.lift off (火箭等)发射;(直升飞机)起飞
They are watching spaceship lift off quietly.
他们静静地看着宇宙飞船起飞
2.hit the ground 着陆
I felt the shock as the aircraft hit the ground.
飞机着陆时我感觉到了震动
3.prototype 原型
This simple device is the prototype of the commercial alternating current generator, or alternator.
这个简单装置就是商用交流发电机的原型
4.bread and butter (某人或公司的)主要收入来源
Out-of-state visitors are our bread and butter.
外省游客是我们的主要经济来源