Original sentence: Conspiracy theorists have claimed that the collapse of the World Trade Center was the result of a controlled demolition.Since the September 11, 2001 attacks, a variety of conspiracy theories have emerged about the attacks which contradict the mainstream account of events that day.The theories typically include suggestions that individuals in the government of the United States knew of the impending attacks and refused to act on that knowledge, or that they played a role in the attacks
Edited sentence: ' These alternative accounts typically include suggestions that individuals in the government of the United States knew of the impending attacks and refused to act on that knowledge, or that they played a role in the attacks.9/11 Researchers have claimed that the collapse of the World Trade Center was the result of a controlled demolition.Since the September 11, 2001 attacks, a variety of explanations have emerged about the attacks that contradict the mainstream account of events that day.These alternative accounts are often described, both by the mainstream media and by detractors, as '9/11 conspiracy theories