(S (S (CC But) (S (NP (BASENP (NNS survivors)) (PP (IN of) (BASENP (DT the) (NN attack)))) (VP (VBP argue) (SBAR (IN that) (S (BASENP (DT a) (ADJP (RB fully) (JJ comprehensive)) (NN investigation)) (VP (MD could) (VP (VB teach) (NP (BASENP (JJ valuable) (NNS lessons)) (SBAR (WHNP (WDT which)) (S (VP (MD may) (VP (VP (VB help) (S (VP (VB reduce) (NP (BASENP (DT the) (NN likelihood)) (PP (IN of) (BASENP (JJ future) (NNS attacks))))))) (CONJP (COMMA ,) (CC and)) (VP (VB improve) (NP (BASENP (DT the) (NN response) (NNS capabilities)) (PP (IN of) (BASENP (DT the) (JJ emergency) (NNS services))))))))))))))))) (PERIOD .))