( ( Opaque materials ) ( ( ( do not ) ( allow ( light ( to ( pass ( through them ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Opaque) (NNS materials)) (VP (VBP do) (RB not) (VP (VB allow) (ADJP (JJ light) (S (VP (TO to) (VP (VB pass) (PP (IN through) (NP (PRP them))))))))) (. .)))
Opaque materials do not allow light to pass through them.
(ROOT (S (NP (NNP Opaque)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NN matter))) (SBAR (WHNP (WDT that)) (S (VP (VBZ does) (RB not) (VP (VB let) (NP (DT any) (JJ light) (NN pass)) (PRT (RP through)))))))) (. .)))