( ( ( ( ( ( ( ( The light ) and ) ( the glass ) ) ( never mingle ) ) , ) but ) ( ( as matter ) ( , ( ( the glass ) ( is ( less ( opaque ( than ( the walls ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN light)) (CC and) (NP (DT the) (NN glass))) (ADVP (RB never)) (VP (VBP mingle))) (, ,) (CC but) (S (PP (IN as) (NP (NN matter))) (, ,) (NP (DT the) (NN glass)) (VP (VBZ is) (ADJP (RBR less) (JJ opaque) (PP (IN than) (NP (DT the) (NNS walls)))))) (. .)))
The light and the glass never mingle, but as matter, the glass is less opaque than the walls.
(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)))))))) (. .)))