(S (BASENP (DT A) (JJ Canadian) (NN official)) (VP (VBD said) (SBAR (IN that) (QT (DQL ``) (QTC (S (PP (IN As) (BASENP (DT a) (NN precaution))) (COMMA ,) (S (S (BASENP (NNP NORAD) (NNS fighters)) (VP (VBD escorted) (BASENP (DT the) (NN aircraft)))) (SBAR (IN until) (S (BASENP (PRP it)) (VP (VP (VBD landed) (ADVP (RB safely))) (PP (IN in) (BASENP (NNP Vancouver)))))))) (PERIOD .)) (DQR '')))))