( ( Diffuse reflection ) ( ( occurs ( when ( light ( ( reflects off ) ( a ( ( microscopically rough ) surface ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Diffuse) (NN reflection)) (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (NN light)) (VP (VBZ reflects) (PRT (RP off)) (NP (DT a) (ADJP (RB microscopically) (JJ rough)) (NN surface)))))) (. .)))
Diffuse reflection occurs when light reflects off a microscopically rough surface.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN light)) (VP (VBZ reflects) (PP (IN from) (NP (DT a) (JJ rough) (NN surface)))))) (, ,) (NP (PRP it)) (VP (VBZ gets) (ADJP (JJ diffused))) (. .)))