(SINV (SINV (QT (DQR '') (QTC (S (PRN (LRB [) (S (BASENP (PRP We)) (VP (VBP are))) (RRB ])) (VP (VBG trying) (S (VP (TO to) (VP (VB determine) (NP (NP (BASENP (DT the) (NN cause)) (CC or) (BASENP (DT any) (NN threat))) (PP (TO to) (BASENP (DT the) (NN population))))))))) (COMMA ,)) (DQR '')) (SINV (VP (VBD said)) (NP (BASENP (JJ U.S.) (JJ military) (NN spokesman)) (COMMA ,) (NP (BASENP (NNP Lt.) (NNP Col)) (COMMA ,) (BASENP (NNP Christopher) (NNP C.) (NNP Garver)))))) (PERIOD .))