( ( ( The ( three ( main types ) ) ) ( of radioactivity ) ) ( ( are ( ( ( ( ( ( gamma rays ) , ) ( ( fast-moving alpha ) particles ) ) , ) and ) ( beta particles ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (CD three) (JJ main) (NNS types)) (PP (IN of) (NP (NN radioactivity)))) (VP (VBP are) (NP (NP (NN gamma) (NNS rays)) (, ,) (NP (ADJP (JJ fast-moving) (NN alpha)) (NNS particles)) (, ,) (CC and) (NP (JJ beta) (NNS particles)))) (. .)))
The three main types of radioactivity are gamma rays , fast-moving alpha particles , and beta particles .
(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))) (. .)))