Complex sentence: The United States Agency for International Development (USAID) hosted a preview screening for the film at the Willard InterContinental Washington that September, as part of a day-long symposium on the subject of human trafficking.
Split into simpler sentences: The United States Agency for International Development (USAID) hosted a preview screening for the film at the Willard InterContinental Washington that September. The screening was part of a day-long symposium on the subject of human trafficking.