World War 1

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Across
  1. 2. backed out of war in 1917
  2. 5. the area between trench lines
  3. 8. new weapon: shot flames
Down
  1. 1. type of warfare
  2. 3. event that triggered the war
  3. 4. new large vehicular invention
  4. 6. new explosive type of weapon
  5. 7. joined war in 1917