hit that may strain adult credibility . 
(ROOT (S (VP (VBD hit) (SBAR (S (NP (DT that)) (VP (MD may) (VP (VB strain) (NP (JJ adult) (NN credibility))))))) (. .)))
(ROOT (S (VP (VBD ) (SBAR (S (NP (DT )) (VP (MD ) (VP (VB ) (NP (JJ ) (NN ))))))) (. )))