Complex sentence: The Natural Science Forum was renamed Sept.3rd Forum and later in 1945 became Sept.3rd Society (or called Jiusan Society), which is a China organization for intellectual groups.
Split into simpler sentences: The Natural Science Forum was renamed Sept.3rd Forum and later again renamed Sept.3rd Society in 1945. The Sept.3rd Society, or called Jiusan Society, is a China organization for intellectual groups.