Complex sentence: It is awarded to senior cadets shortly after the start of their senior year, after which there is a formal dinner and dance (called a "hop" in cadet slang) following the ceremony for the cadets and their guests.
Split into simpler sentences: It is awarded to senior cadets shortly after the start of their senior year. There is a formal dinner and dance (called a "hop" in cadet slang) following the ceremony for the cadets and their guests.