( ( consisting ( of ( a ( ( cap or ) sac ) ) ) ) ( ( ( shaped ( mass ( of cells ) ) ) ( with ( walls ( of ( ( two layers ) ( of ( cells surrounding ) ) ) ) ) ) ) . ) )
(ROOT (S (S (VP (VBG consisting) (PP (IN of) (NP (DT a) (NN cap) (CC or) (NN sac))))) (VP (VBN shaped) (NP (NP (NN mass)) (PP (IN of) (NP (NNS cells)))) (PP (IN with) (NP (NP (NNS walls)) (PP (IN of) (NP (NP (CD two) (NNS layers)) (PP (IN of) (NP (NP (NNS cells)) (VP (VBG surrounding))))))))) (. .)))
consisting of a cap or sac shaped mass of cells with walls of two layers of cells surrounding.
(ROOT (S (NP (NP (DT The) (NN pleura)) (SBAR (WHNP (WDT that)) (S (VP (VBZ surrounds) (NP (DT the) (NNS lungs)))))) (VP (VBZ consists) (PP (IN of) (NP (CD two) (NNS layers)))) (. .)))