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 ))))))))