On 9/11, the terrorists turned off the transponders on three of the four hijacked aircraft.
( ( On 9/11 ) ( , ( ( the terrorists ) ( ( ( ( turned off ) ( the transponders ) ) ( on ( three ( of ( the ( four ( hijacked aircraft ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN On) (NP (CD 9/11))) (, ,) (NP (DT the) (NNS terrorists)) (VP (VBD turned) (PRT (RP off)) (NP (DT the) (NNS transponders)) (PP (IN on) (NP (NP (CD three)) (PP (IN of) (NP (DT the) (CD four) (JJ hijacked) (NN aircraft)))))) (. .)))
One of the four hijacked airplanes did not consider the consequences of having an active transponder.
( ( One ( of ( the ( four ( hijacked airplanes ) ) ) ) ) ( ( ( did not ) ( consider ( ( the consequences ) ( of ( having ( an ( active transponder ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (CD One)) (PP (IN of) (NP (DT the) (CD four) (JJ hijacked) (NNS airplanes)))) (VP (VBD did) (RB not) (VP (VB consider) (NP (NP (DT the) (NNS consequences)) (PP (IN of) (S (VP (VBG having) (NP (DT an) (JJ active) (NN transponder)))))))) (. .)))