(S (S (NP (BASENP (DT The) (NN cause)) (PP (IN of) (BASENP (DT the) (NN crash)))) (VP (VP (VP (VBZ is) (ADVP (RB still))) (ADJP (JJ unknown))) (COMMA ,) (PP (VBG pending) (BASENP (DT an) (JJ official) (NN investigation))))) (PERIOD .))