A bloody trench warfare continued for over___.

Explanation:

The French built the 19-kilometre-long (12 mi) Lines of Weissenburg during the War of the Spanish Succession under the orders of the Duke of Villars in 1706. These were to remain in existence for just over 100 years and were last manned during Napoleon's Hundred Days (1815). Although trench warfare was very important throughout the war, the strategy neared an end around 1918, beginning with the Kaiser's Battle.

it was a act of seld fesnse more over it was a peace treaty between the fogein contunries.

they wanted the u.s. to fight on the side of the central powers.