( ( The ( nuclear ( chain reaction ) ) ) ( ( ( was not ) ( ( brought ( under control ) ) ( until ( ( the evening ) ( of ( Oct. 1 ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ nuclear) (NN chain) (NN reaction)) (VP (VBD was) (RB not) (VP (VBN brought) (PP (IN under) (NP (NN control))) (PP (IN until) (NP (NP (DT the) (NN evening)) (PP (IN of) (NP (NNP Oct.) (CD 1))))))) (. .)))
The nuclear chain reaction was not brought under control until the evening of Oct. 1.
(ROOT (S (NP (NNP Control) (NNS rods)) (VP (VBP play) (NP (NP (DT an) (JJ important) (NN role)) (PP (IN in) (NP (NP (DT the) (NN modulation)) (PP (IN of) (NP (DT the) (JJ nuclear) (NN chain) (NN reaction))))))) (. .)))