(S (S (BASENP (DT Each) (NN week)) (S (NP (BASENP (QP (RB approximately) (NN 70)) (NN percent)) (PP (IN of) (BASENP (JJ non-smoking) (NNS adults)))) (VP (VBP are) (VP (VBN exposed) (PP (TO to) (BASENP (JJ second-hand) (NN smoke))))))) (PERIOD .))