( ( ( A number ) ( of instructions ) ) ( ( allow ( ( atom names ) ( to ( be referenced ) ) ) ) ; ) )
(ROOT (S (NP (NP (DT A) (NN number)) (PP (IN of) (NP (NNS instructions)))) (VP (VBP allow) (S (NP (NN atom) (NNS names)) (VP (TO to) (VP (VB be) (VP (VBN referenced)))))) (: ;)))
A number of instructions allow atom names to be referenced;
(ROOT (S (NP (NP (DT The) (JJ low) (JJ atomic) (NN number)) (PP (IN of) (NP (NN beryllium)))) (VP (VBZ allows) (S (NP (PRP it)) (VP (TO to) (VP (VB absorb) (NP (NNPS x-rays)))))) (. .)))