Complex sentence: Austen Crehore attended Hackensack Public Schools until the beginning of The First World War on March 1,1917, He desperately tried to enter the US Army Air Service and then the US Naval Aviation.
Split into simpler sentences: Austen Crehore attended Hackensack Public Schools until the beginning of the First World War on March 1,1917. He tried to enter the US Army Air Service and then the US Naval Aviation.