( ( In general ) ( there ( ( are ( ( four ( major classes ) ) ( of ( compounds ( that ( comprise ( most ( biological materials ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (NN general))) (NP (EX there)) (VP (VBP are) (NP (NP (CD four) (JJ major) (NNS classes)) (PP (IN of) (NP (NP (NNS compounds)) (SBAR (WHNP (WDT that)) (S (VP (VBP comprise) (NP (RBS most) (JJ biological) (NNS materials))))))))) (. .)))
In general there are four major classes of compounds that comprise most biological materials.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD four) (NNS classes)) (PP (IN of) (NP (JJ biochemical) (NNS compounds))))) (. .)))