is why i have given it a one-star rating . 
(ROOT (SINV (VP (VBZ is)) (SBAR (WHADVP (WRB why)) (S (NP (PRP i)) (VP (VBP have) (VP (VBN given) (NP (PRP it)) (NP (DT a) (NML (CD one) (HYPH -) (NN star)) (NN rating)))))) (. .)))
(ROOT (SINV (VP (VBZ )) (SBAR (WHADVP (WRB )) (S (NP (PRP )) (VP (VBP ) (VP (VBN ) (NP (PRP )) (NP (DT ) (NML (CD ) (HYPH ) (NN )) (NN )))))) (. )))