Complex sentence: During the Second World War, the British administrators converted the school into a military hospital, when the British's troops surrendered to the Japanese government, the school was turned into the Gunsei Kanbu or the Japanese military headquarters.
Split into simpler sentences: During the Second World War, the British administrators converted the school into a military hospital. When the British troops surrendered to the Japanese government, the school was turned into a Gunsei Kanbu or Japanese military headquarters.