( Weight ( ( is ( ( a force ) ( caused ( by gravity ) ) ) ) . ) )
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT a) (NN force)) (VP (VBN caused) (PP (IN by) (NP (NN gravity)))))) (. .)))
Weight is a force caused by gravity.
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT the) (NN result)) (PP (IN of) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN gravity)) (VP (VBG being) (VP (VBN opposed) (PP (IN by) (NP (DT the) (JJ normal) (NN force))))))))))) (. .)))