(S (S (BASENP (PRP He)) (VP (VBD said) (SBAR (IN that) (S (BASENP (PRP he)) (VP (VBD was) (ADJP (JJ uncertain) (PP (IN of) (SBAR (WHNP (WHADJP (WRB how) (JJ many)) (NNS flights)) (S (VP (VBD were) (VP (VBN affected) (PP (JJ due) (PP (TO to) (BASENP (DT the) (NN eruption))))))))))))))) (PERIOD .))