(S (S (NP (BASENP (NN Two) (JJ Canadian) (NN navy) (NNS ships)) (CC and) (NP (BASENP (NN two) (NN airforce) (NNS planes)) (PRN (COMMA ,) (NP (BASENP (DT a) (NNP CC-138) (NNP Twin) (NNP Otter)) (CC and) (BASENP (DT a) (NNP CP-140) (NNP Aurora))) (COMMA ,)))) (VP (VBD took) (NP (BASENP (NN part)) (PP (IN in) (NP (BASENP (DT the) (NNS exercises)) (PP (IN in) (NP (DT the) (NP (BASENP (NNP Canada) (POS 's)) (NNP Arctic))))))))) (PERIOD .))