Originally Posted by Jim_Gunn

You need to know history to understand his comments. He's saying that the anniversary for the U.S.'s involvement in World War 1 wouldn't be this year, 2014, because the US didn't officially enter WW1 until 1917, three years after it had started in Europe. Similar to how the U.S. didn't engage in the heaviest ground fighting on the Continent in WW2 until much later at D-Day in 1944 as opposed to the European antagonists who were fighting as early as 1939.