(S (S (BASENP (NNP AP)) (VP (VBD reported) (SBAR (IN that) (S (BASENP (DT this)) (VP (VBZ is) (SBAR (IN because) (S (NP (EX there)) (VP (VP (VBZ is) (BASENP (DT a) (JJ low) (NN oxygen) (NN level))) (PP (IN in) (BASENP (DT the) (NN cellar))))))))))) (PERIOD .))