填空题

On Sept. 11, the nation’s aviation system quickly and safely landed almost 4,500 planes that were in the air when the terrorist attacks took place. How was this (S1)_________ What was it tike inside air traffic control centers and at airline (S2)___________ How was the decision made to land all the planes And how did controllers execute it Some USA TODAY reporters spent seven months (S3)______________more than 100 people involved in key decisions that day. The reporters traveled to New York, Washington, Chicago, Texas and Atlanta. The (S4)________, thoughts and quotes in the stories are based on interviews with (S5) _____________or with sources who had (S6)__________to tape recordings. Accounts of the day’s events were (S7)___________. Reporters and editors also scrutinized hundreds of pages of records, including (S8)_________of radio calls with the four hijacked jets and a log kept by the Federal Aviation Administration. (S9)_____________________. A key source was the FAA radar data from the Traffic Situation Display. The system tracks all aircraft in the United States and Canada that have filed flight plans: (S10)_________________________It also estimates the location of planes over the Atlantic and Pacific oceans flying to and from North America. S9