( ( The reflection ) ( ( is ( ( called diffuse ) ( if ( ( the ( reflecting surface ) ) ( is rough ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN reflection)) (VP (VBZ is) (VP (VBN called) (ADJP (JJ diffuse)) (SBAR (IN if) (S (NP (DT the) (JJ reflecting) (NN surface)) (VP (VBZ is) (ADJP (JJ rough))))))) (. .)))
The reflection is called diffuse if the reflecting surface is rough.
(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))) (. .)))