(UCP (LST (LS :) (LS :)) (UCP (BASENP (NNP Sarah) (NNP Walsh)) (COLON :) (S (S (NP (EX There)) (VP (MD could) (VP (VB be) (NP (BASENP (DT a) (NN number)) (PP (IN of) (BASENP (JJ contributing) (NNS factors))))))) (PERIOD .))))