(S (S (NP (BASENP (JJS Most)) (PP (IN of) (BASENP (DT the) (NNS passengers)))) (VP (VBD were) (NP (BASENP (NNS schoolchildren)) (VP (VBN returning) (PP (IN from) (BASENP (DT a) (NN ski) (NN trip))))))) (PERIOD .))