Complex sentence: The 1955 Montreal 3rd World Conference of the International Jewish Labor Bund decided that the creation of the Jewish state was an important event in Jewish history that might play a positive role in Jewish life, yet a few necessary changes were needed.
Split into simpler sentences: The 1955 Montreal Third world conference of the International Jewish Labor Bund decided that the creation of the Jewish state was an important event in the Jewish history. The state might play a positive role in the Jewish life but a few necessary changes were needed.