(S (S (NP (BASENP (DT Neither)) (PP (IN of) (BASENP (DT these) (NNS factors)))) (VP (VBP have) (VP (VBN been) (VP (VP (VBN linked) (PP (TO to) (NP (BASENP (DT the) (NN cause)) (PP (IN of) (BASENP (DT the) (NN crash)))))) (PP (IN at) (BASENP (DT this) (NN point))))))) (PERIOD .))