one that should be thrown back in the river 
(ROOT (NP (NP (CD one)) (SBAR (WHNP (WDT that)) (S (VP (MD should) (VP (VB be) (VP (VBN thrown) (ADVP (RB back)) (PP (IN in) (NP (DT the) (NN river))))))))))
(ROOT (NP (NP (CD )) (SBAR (WHNP (WDT )) (S (VP (MD ) (VP (VB ) (VP (VBN ) (ADVP (RB )) (PP (IN ) (NP (DT ) (NN ))))))))))