( ( Gamma rays ) ( ( ( ( ( are ( ( the ( most penetrating ) ) ( of ( ( the ( three ( common types ) ) ) ( of radiation ) ) ) ) ) ( -LRB- ( ( ( the ( other two ) ) ( are ( alpha ( particles ( and ( beta particles ) ) ) ) ) ) -RRB- ) ) ) and ) ( are ( best ( stopped ( by ( ( dense materials ) ( such ( as lead ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Gamma) (NNS rays)) (VP (VP (VBP are) (NP (NP (DT the) (JJS most) (NN penetrating)) (PP (IN of) (NP (NP (DT the) (CD three) (JJ common) (NNS types)) (PP (IN of) (NP (NN radiation))))))) (PRN (-LRB- -LRB-) (S (NP (DT the) (JJ other) (CD two)) (VP (VBP are) (VP (VBG alpha) (NP (NNS particles) (CC and) (NN beta) (NNS particles))))) (-RRB- -RRB-)) (CC and) (VP (VBP are) (VP (RBS best) (VBN stopped) (PP (IN by) (NP (NP (JJ dense) (NNS materials)) (PP (JJ such) (IN as) (NP (NN lead)))))))) (. .)))
Gamma rays are the most penetrating of the three common types of radiation (the other two are alpha particles and beta particles ) and are best stopped by dense materials such as lead.
(ROOT (S (PP (IN Of) (NP (NP (DT the) (CD three) (JJ basic) (NNS types)) (PP (IN of) (NP (JJ radioactive) (NNS emissions))))) (, ,) (NP (DT the) (NN gamma) (NN particle)) (VP (VBZ is) (NP (DT the) (JJS most) (NN penetrating))) (. .)))