(S (S (NP (BASENP (NN Pentobarbital)) (PRN (COMMA ,) (NP (BASENP (DT an) (NN alternative)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (VP (VBN used) (PP (IN at) (NP (BASENP (DT the) (NNP Dignitas) (NN clinic)) (PP (IN in) (BASENP (NNP Switzerland)))))))))) (COMMA ,))) (VP (VP (VBZ is) (VP (VBN used) (PP (IN for) (NP (BASENP (JJ lethal) (NNS injections)) (PP (IN in) (BASENP (NNP Oregon))))))) (CONJP (COMMA ,) (CC and)) (VP (VBZ has) (VP (VBN started) (S (VP (TO to) (VP (VB be) (VP (VBN used) (PP (IN by) (BASENP (NNP Oklahoma))))))))))) (PERIOD .))