( ( A ( nonrenewable resource ) ) ( ( ( can not ) ( be ( replaced ( once ( it ( is ( used up ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ nonrenewable) (NN resource)) (VP (MD can) (RB not) (VP (VB be) (VP (VBN replaced) (SBAR (IN once) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN used) (PRT (RP up))))))))) (. .)))
A nonrenewable resource cannot be replaced once it is used up.
(ROOT (S (NP (JJ Nonrenewable) (NNS resources)) (VP (MD can) (RB not) (VP (VB be) (VP (VBN replaced) (ADVP (ADVP (RB as) (RB easily)) (SBAR (IN as) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN consumed))))))))) (. .)))