text:  The 90-minute debate will feature two commercial breaks. No staffers will be allowed on stage. A two-minute answer to each question will be followed by a one-minute rebuttal and then a response to that rebuttal. CNN has agreed to mute the microphone of the candidate who isn't recognized to speak. By a coin toss, it's been determined that Biden will give the first two-minute closing statement and Trump will have the last word. ABC's Stephen Portnoy in Shanghai.