Instruction and study (2) Intercession (2) Propaganda (2) World War, 1914-1918 (2) War (2) Time (2) Tanks (Military science) (2) Sphere (2) Soldiers (2) New and old (2) Mechanical movements (2) Industrialists (2) Fortitude (2) Fire (2) Engines of war (2) Encouragement (2) Courage (2) Alliances (2) Trench warfare (2) Science (2) Battlefields (2) Practice (2) Forecasting (2) Experiments (2) Peace (2) Valentía (2) Esfera (2) Mecanismos (2) Fortaleza (2) Ciencias (2)