Complex sentence: Carolgees went on to work alongside Cilla Black in "Surprise, Surprise" and he was for nearly two decades one of the foremost entertainers to entertain the British armed forcesaround the world.
Split into simpler sentences: Carolgees went on to work alongside Cilla Black in "Surprise, Surprise" and he has entertained the armed forces. For nearly two decades he was one of the foremost entertainers to entertain British armed forces around the world.