At 9:03, United 175 crashed into the South Tower.
( ( At 9:03 ) ( , ( ( United 175 ) ( ( crashed ( into ( the ( South Tower ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (CD 9:03))) (, ,) (NP (NNP United) (CD 175)) (VP (VBD crashed) (PP (IN into) (NP (DT the) (NNP South) (NNP Tower)))) (. .)))
United 175 crashed into the South Tower at 9:03.
( ( United 175 ) ( ( ( crashed ( into ( the ( South Tower ) ) ) ) ( at 9:03 ) ) . ) )
(ROOT (S (NP (NNP United) (CD 175)) (VP (VBD crashed) (PP (IN into) (NP (DT the) (NNP South) (NNP Tower))) (PP (IN at) (NP (CD 9:03)))) (. .)))