( ( Many ( ( -LRB- ( ( if ( not most ) ) -RRB- ) ) birds ) ) ( ( have ( four ( cone classes ) ) ) . ) )
(ROOT (S (NP (JJ Many) (PRN (-LRB- -LRB-) (PP (IN if) (NP (RB not) (RB most))) (-RRB- -RRB-)) (NNS birds)) (VP (VBP have) (NP (CD four) (NN cone) (NNS classes))) (. .)))
Many (if not most) birds have four cone classes.
(ROOT (S (NP (NNP Birds)) (VP (VBP have) (NP (CD four) (NNS limbs))) (. .)))