"Ambush", O'Brien describes killing a man while serving in war. He had no intention of killing him-- he reacted without thinking. O'Brien feels guilty about having killed another human being, even though his fellow soldier tries to soothe him with the logic that the man would have been killed eventually anyway. However, trying to justify having killed someone, O'Brien explains that his training as a soldier prompted him to act involuntarily when he lobbed the grenade upon spotting an enemy soldier. Twenty years later, long after the war has ended, O'Brien is unable to admit to his daughter, Kathleen, that he has killed another. He feels guilt and denial about having killed a man, and experiences recurrent flashbacks and visions. Through his story, O'Brien conveys that a soldier is a changed person after he has witnessed such a war, and those who have not been in a war cannot begin to understand the emotional turmoil that soldiers go through.
well, number 1, the 1920s was not economically prosperous until the start of the lend-lease act, which employed large amounts of people in producing equipment for the allies.
b. world war ii is your answer, because wwi had already ended at 1918, and the cold war was after 1945.