( Typically ( , ( amphibians ( ( have ( four limbs ) ) . ) ) ) )
(ROOT (S (ADVP (RB Typically)) (, ,) (NP (NNS amphibians)) (VP (VBP have) (NP (CD four) (NNS limbs))) (. .)))
Typically, amphibians have four limbs.
(ROOT (S (NP (NNP Birds)) (VP (VBP have) (NP (CD four) (NNS limbs))) (. .)))