( ( particle ( ( physical properties ) ( such ( as ( ( density and ) ( elastic modulus ) ) ) ) ) ) ; )
(ROOT (S (VP (VBG particle) (NP (NP (JJ physical) (NNS properties)) (PP (JJ such) (IN as) (NP (NP (NN density)) (CC and) (NP (JJ elastic) (NNS modulus)))))) (: ;)))
particle physical properties such as density and elastic modulus;
(ROOT (S (NP (NP (NNP Density)) (PP (IN of) (NP (NN matter)))) (VP (VBZ reflects) (SBAR (WHADVP (WRB how) (RB closely)) (S (VP (VBD packed) (SBAR (S (NP (NP (DT the) (NNS particles)) (PP (IN of) (NP (NN matter)))) (VP (VBP are)))))))) (. .)))