一线二线无人区乱码

　　In the history of warfare there have been a catalogue of inventions that have changed the way battles are fought. The catapult, the longbow, the cannon, the machine gun. But one weapon changed not only the battlefield, but war itself. It extended the scope of military conflict to the far borders of entire nations and unleashed a terror the world had never known. 　　That weapon was... (展开全部)