( ( Sometimes ( it ( ( wo n't ) ( make ( ( ( any ( ( noise or ) grinding ) ) but ) ( most ( of ( the time ) ) ) ) ) ) ) ) ( it ( does . ) ) )
(ROOT (S (S (ADVP (RB Sometimes)) (NP (PRP it)) (VP (MD wo) (RB n't) (VP (VB make) (NP (NP (DT any) (NN noise) (CC or) (VBG grinding)) (CC but) (NP (NP (JJS most)) (PP (IN of) (NP (DT the) (NN time)))))))) (NP (PRP it)) (VP (VBZ does)) (. .)))
Sometimes it won't make any noise or grinding but most of the time it does.
(ROOT (S (NP (NN Ground) (NN tissue)) (VP (VBZ makes) (PRT (RP up)) (NP (NP (JJS most)) (PP (IN of) (NP (NP (DT the) (NN inside)) (PP (IN of) (NP (DT a) (NN plant))))))) (. .)))