The helicopter landed safely.直升机安全降落了。
A helicopter has been sent to pick up the sick man from the sea.已经派出一架直升机去接回海上的病员。
Helicopters can go up and come down in a straight line, and can also stay still in the air.直升机能直线上升或下降,也能在空中停住不动。
He is a helicopter pilot.他是一名直升机驾驶员。
