some episodes work , some do n't . 
(ROOT (S (S (NP (DT some) (NNS episodes)) (VP (VBP work))) (, ,) (S (NP (DT some)) (VP (VBP do) (RB n't))) (. .)))
(ROOT (S (S (NP (DT ) (NNS )) (VP (VBP ))) (, ) (S (NP (DT )) (VP (VBP ) (RB ))) (. )))