( ( Nonrenewable ( ( resources resources ) ( that ( ( can not ) ( be ( replaced ( once ( they ( have ( been used ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Nonrenewable) (NP (NP (NNS resources) (NNS resources)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (RB not) (VP (VB be) (VP (VBN replaced) (SBAR (IN once) (S (NP (PRP they)) (VP (VBP have) (VP (VBN been) (VP (VBN used))))))))))))) (. .)))
Nonrenewable resources resources that cannot be replaced once they have been used.
(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))))))))) (. .)))