( ( diffuse reflection ) ( ( occurs ( on ( ( ( uneven surfaces ) , ) ( when ( light scatters ) ) ) ) ) . ) )
(ROOT (S (NP (JJ diffuse) (NN reflection)) (VP (VBZ occurs) (PP (IN on) (NP (NP (JJ uneven) (NNS surfaces)) (, ,) (SBAR (WHADVP (WRB when)) (S (NP (NN light)) (VP (VBZ scatters))))))) (. .)))
diffuse reflection occurs on uneven surfaces, when light scatters.
(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))) (. .)))