Complex sentence: On 1 July 1903, the Adelaide Rifles became the 10th Infantry Regiment of the Commonwealth Military Forces, and Weir was appointed as adjutant, before being promoted to major on 1 January 1904, and appointed as regimental second-in-command.
Split into simpler sentences: On 1 July 1903, the Adelaide Rifles became the 10th Infantry Regiment of the Commonwealth Military Forces, and Weir was appointed adjutant. He was promoted to major on 1 January 1904, and appointed as regimental second-in-command.