( ( ( ( ( Mercury Mercury ) , ) ( symbol Hg ) ) , ) ( ( is ( ( the ( only metal ) ) ( that ( is ( a ( ( liquid ( at room ) ) temperature ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Mercury) (NNP Mercury)) (, ,) (NP (NN symbol) (NN Hg)) (, ,)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN metal)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (NP (DT a) (ADJP (JJ liquid) (PP (IN at) (NP (NN room)))) (NN temperature))))))) (. .)))
Mercury Mercury, symbol Hg, is the only metal that is a liquid at room temperature.
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (NP (NP (DT the) (CD one) (NN metal)) (SBAR (WHNP (WDT that)) (S (VP (VBZ melts) (PP (IN below) (NP (NN room) (NN temperature)))))))) (. .)))