(S (S (BASENP (DT The) (NN parents)) (VP (VP (VBD aired) (NP (BASENP (PRPD their) (NNS concerns)) (PP (IN over) (NP (NP (BASENP (NN health) (NNS issues)) (PP (IN at) (BASENP (NNS schools) (CC and) (NNS workplaces)))) (COMMA ,) (PP (VBG including) (NP (BASENP (DT a) (NN rash)) (PP (IN of) (NP (BASENP (NN leukemia) (NNS cases)) (PP (IN in) (BASENP (DT the) (NN student) (NN population))))))))))) (CONJP (COMMA ,) (CC and)) (VP (VBD began) (NP (BASENP (DT a) (NN dialogue)) (SBAR (S (BASENP (PRP they)) (VP (VBP have) (VP (VBN been) (VP (VP (VBG working) (PP (IN toward))) (PP (IN for) (BASENP (NNS years)))))))))))) (PERIOD .))