Answer:
They had been building up their strength and had fresh new troops
Explanation:
The United States was bordering on if they wanted to join the war against the central powers( Germany, Austria-Hungary, Ottoman Empire, and Bulgaria) or if they should just sit it out. The United States was selling supplies to the allies on the western front of the war, and after Russia capitulated, the allies(United Kingdom, Belgium, Serbia, formerly Russia, and France) desperately needed these supplies, the Germans did not like that the US was selling supplies to the allies, so King Wilhelm II sent a telegram to Mexico saying that if they attacked the US, they would benefit from it via Germany. Luckily, the British intercepted this telegram and showed it to the United States president at that time, Woodrow Wilson, which was the final straw for America. As I stated earlier, America was selling supplies to the allies in Europe, and their economy was booming because of it. What this means is that by the time of the United States entry in the war, they had buffed up their military and had fresh, eager troops to send to Europe. When Germany found out about this, they knew if they did not do something soon, they would be defeated, and so they made several large offensives in France, most of which were successful, but at the same time they were draining their resources while the allies got better at defending against them. With fresh American troops in the fight, the Germans were pushed back and they capitulated on November 11th, 1918, Germany was the last country to capitulate, following Autria-Hungary and the Ottoman Empire.
