it 's not an easy one to review . 
(ROOT (S (NP (PRP it)) (VP (VBZ 's) (RB not) (NP (NP (DT an) (JJ easy) (NN one)) (SBAR (S (VP (TO to) (VP (VB review))))))) (. .)))
(ROOT (S (NP (PRP )) (VP (VBZ ) (RB ) (NP (NP (DT ) (JJ ) (NN )) (SBAR (S (VP (TO ) (VP (VB ))))))) (. )))