The Command Center executed the request and, a minute later, Cleveland Center reported that United 93 may have a bomb on board.
( ( ( ( ( ( The ( Command Center ) ) ( executed ( the request ) ) ) and ) , ) ( ( ( a minute ) later ) ( , ( ( Cleveland Center ) ( reported ( that ( ( United 93 ) ( may ( have ( ( a bomb ) ( on board ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT The) (NNP Command) (NNP Center)) (VP (VBD executed) (NP (DT the) (NN request)))) (CC and) (, ,) (S (ADVP (NP (DT a) (NN minute)) (RB later)) (, ,) (NP (NNP Cleveland) (NNP Center)) (VP (VBD reported) (SBAR (IN that) (S (NP (NNP United) (CD 93)) (VP (MD may) (VP (VB have) (NP (NP (DT a) (NN bomb)) (PP (IN on) (NP (NN board)))))))))) (. .)))
A minute after the Command Center executed the request the Cleveland Center reported that flight of United 93 may have a bomb on board.
( ( ( A minute ) ( after ( the ( Command Center ) ) ) ) ( ( executed ( ( the request ) ( ( the ( Cleveland Center ) ) ( reported ( that ( ( flight ( of ( United 93 ) ) ) ( may ( have ( ( a bomb ) ( on board ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN minute)) (PP (IN after) (NP (DT the) (NNP Command) (NNP Center)))) (VP (VBD executed) (NP (NP (DT the) (NN request)) (SBAR (S (NP (DT the) (NNP Cleveland) (NNP Center)) (VP (VBD reported) (SBAR (IN that) (S (NP (NP (NN flight)) (PP (IN of) (NP (NNP United) (CD 93)))) (VP (MD may) (VP (VB have) (NP (NP (DT a) (NN bomb)) (PP (IN on) (NP (NN board))))))))))))) (. .)))