( Laws ( ( ( ( ( are ( ( ( purely descriptive ) statements ) ( about nature ) ) ) , ) and ) ( ( do not ) ( ( explain ( the phenomena ) ) ( that ( they describe ) ) ) ) ) ; ) )
(ROOT (S (NP (NNS Laws)) (VP (VP (VBP are) (NP (NP (ADJP (RB purely) (JJ descriptive)) (NNS statements)) (PP (IN about) (NP (NN nature))))) (, ,) (CC and) (VP (VBP do) (RB not) (VP (VB explain) (NP (DT the) (NNS phenomena)) (SBAR (IN that) (S (NP (PRP they)) (VP (VBP describe))))))) (: ;)))
Laws are purely descriptive statements about nature, and do not explain the phenomena that they describe;
(ROOT (S (NP (NP (DT A) (NN statement)) (SBAR (WHNP (WDT that)) (S (VP (VBZ describes) (SBAR (WHNP (WP what)) (S (ADVP (RB always)) (VP (VBZ happens) (PP (IN under) (NP (NP (JJ certain) (NNS conditions)) (PP (IN in) (NP (NN nature)))))))))))) (VP (VBZ is) (ADVP (RB also)) (VP (VBN known) (PP (IN as) (NP (JJ scientific) (NN law))))) (. .)))