Complex sentence: The Air Training Corps (ATC), commonly known in the United Kingdom as the Air Cadets, is a British cadet organisation; a voluntary youth group which is part of the Air Cadet Organisation (ACO) and the Royal Air Force (RAF).
Split into simpler sentences: The Air Training Corps (ATC), commonly known as the Air Cadets, is a cadet organisation based in the United Kingdom. It is a voluntary youth group which is part of the Air Cadet Organisation (ACO) and the Royal Air Force (RAF).