Original sentence: The September 11, 2001 attacks (often referred to as 9/11—pronounced "nine eleven") consisted of a series of coordinated suicide attacks by Islamic extremists on that date upon the United States of America
Edited sentence: The September 11, 2001 attacks (often referred to as 9/11—pronounced "nine eleven") consisted of a series of coordinated terrorist suicide attacks by Islamic extremists on that date upon the United States of America