The war on other fronts
There seemed little chance of making a decisive breakthrough on the Western Front - both sides were too strong. The Germans were every bit as determined to win the war as the French and British. One British officer after the battle of the Somme in 1916 described the German machine-gunners as "splendid fellows. Fight until they are killed. They gave us hell".
There were two main battle fronts - the Western front in France and Belgium and the Eastern front, which was mostly in Russia and stretched for 900 miles. Here the Russians fought both Germany and Austria-Hungary. There were other areas of fighting: the Gallipoli peninsula in Turkey (an ally of the Central Powers - Germany and Austria-Hungary); in the Turkish Empire in the Middle East, and in north-eastern Italy. The Gallipoli campaign in 1915 was an attempt by the British, Australian and New Zealand Army Corps (ANZACS) to knock Turkey out of the war and link up with the Russians. It was a disastrous failure. Italy entered the war in 1915 on the side of the Entente Powers and fought mainly against the Austrians.
Russia defeated
There were hopes that Russia´s army of 1.3 million men might drive back the Germans on the Eastern Front and there was indeed a breakthrough on this front in early 1918. Unfortunately for the Allies, the breakthrough was German. After the Communists came to power in Russia in November 1917, during the Bolshevik Revolution, they promised to make peace with Germany. In March 1918 they did just that and Germany suddenly found herself with two million men available for an offensive on the Western Front now that they were no longer needed to fight the Russians.
Neil Demarco: Britain and the Great War; Oxford University Press, 1992/2000, page 14