Complex sentence: Fighting in the European theater during World War II, this unit became the most heavily decorated unit for its size and length of service in the history of the United States Army, as well as one of the units with the highest casualty rates.
Split into simpler sentences: Fighting in the European theater during World War II, this unit became the most heavily decorated unit for its size and length of service in the history of the United States Army. As well as one of the units with the highest casualty rates.