Complex sentence: However, the overall tone of the movie is innacurate because of the prominent roles of the American characters in the film, since the real-life American POWs had a minor role in the actual escape, which was largely a British affair.
Split into simpler sentences: However, the overall tone of the movie is innacurate because of the prominent roles of the American characters in the film. The real-life American POWs had a minor role in the actual escape, which was largely a British affair.