, one the public rarely sees . 
(ROOT (S (, ,) (NP (NP (CD one)) (SBAR (S (NP (DT the) (NN public)) (ADVP (RB rarely)) (VP (VBZ sees))))) (. .)))
(ROOT (S (, ) (NP (NP (CD )) (SBAR (S (NP (DT ) (NN )) (ADVP (RB )) (VP (VBZ ))))) (. )))