Final answer:
The first American soldiers reached France in 1918 and, although initially unprepared, they quickly became crucial in several key battles, helping to turn the tide of the war in favor of the Allies.
Step-by-step explanation:
The first American soldiers reached France in 1918. After they arrived, it took several months of preparation before they were fully ready for battle. During the early spring, US training camps were still ramping up to full capacity. Throughout the summer and fall of 1918, a quarter-million troops were arriving each month. General Pershing initially hoped his troops would have a year to train, but the urgent circumstances on the Western Front forced US troops into action sooner. Key engagements where the newly arrived US forces made a significant impact included the battles of Cantigny, Chateau-Thierry, and Belleau Wood. By July 1918, the numerous divisions of US troops in France were instrumental in helping to turn the tide in favor of the Allies.