The press 秦岭 North, with countless honey dancing on the hill ladder fields. In the spring, the colours of the earth were changed to the open space. The South Korean village in the town of Gansu, is active. The sound of Mada has suddenly been sounded in a quiet wheat. One six-wing unmanned aerial vehicle was vacated and was parked in a half-metre-high air, roting and moving. On the ground, the technician, Liu, has a remote-controlled device, which looks at smart screens. He controls unmanned a...