( ( While ( responding ( to ( these ( concerned people ) ) ) ) ) ( , ( ( ( the captains ) ( of ( the port ) ) ) ( ( must ( lead ( efforts ( ( ( to ( stop ( the pollution ) ) ) and ) ( to ( begin clean-up ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN While) (S (VP (VBG responding) (PP (TO to) (NP (DT these) (VBN concerned) (NNS people)))))) (, ,) (NP (NP (DT the) (NNS captains)) (PP (IN of) (NP (DT the) (NN port)))) (VP (MD must) (VP (VB lead) (S (NP (NNS efforts)) (VP (VP (TO to) (VP (VB stop) (NP (DT the) (NN pollution)))) (CC and) (VP (TO to) (VP (VB begin) (NP (JJ clean-up)))))))) (. .)))
While responding to these concerned people, the captains of the port must lead efforts to stop the pollution and to begin clean-up.
(ROOT (S (NP (NNS People)) (VP (VBD stopped) (S (VP (VBG adding) (NP (NN lead)) (PP (TO to) (NP (NP (NN gasoline)) (PP (RB because) (IN of) (NP (JJ environmental) (NN pollution)))))))) (. .)))