( ( ( The function ) ( of ( the thymus ) ) ) ( ( is ( to ( produce ( mature ( T cells ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN function)) (PP (IN of) (NP (DT the) (NNS thymus)))) (VP (VBZ is) (S (VP (TO to) (VP (VB produce) (NP (JJ mature) (NNP T) (NNS cells)))))) (. .)))
The function of the thymus is to produce mature T cells.
(ROOT (S (NP (DT The) (NNS thymus) (NN gland)) (VP (VBZ produces) (NP (NN t) (NNS cells))) (. .)))