( ( ( ( ( ( ( The rate ) ( of decay ) ) ( ( is conveniently ) ( expressed ( in ( terms ( of ( ( an ( isotope 's ) ) half-life ) ) ) ) ) ) ) , ) or ) ( ( the time ) ( it ( ( takes ( for ( one-half ( of ( ( a ( particular ( radioactive isotope ) ) ) ( in ( a sample ) ) ) ) ) ) ) ( to decay ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN rate)) (PP (IN of) (NP (NN decay)))) (VP (VBZ is) (ADVP (RB conveniently)) (VP (VBN expressed) (PP (IN in) (NP (NP (NNS terms)) (PP (IN of) (NP (NP (DT an) (NN isotope) (POS 's)) (NN half-life)))))))) (, ,) (CC or) (S (NP (DT the) (NN time)) (NP (PRP it)) (VP (VBZ takes) (PP (IN for) (NP (NP (NN one-half)) (PP (IN of) (NP (NP (DT a) (JJ particular) (NN radioactive) (NN isotope)) (PP (IN in) (NP (DT a) (NN sample))))))) (PP (TO to) (NP (NN decay))))) (. .)))
The rate of decay is conveniently expressed in terms of an isotope's half-life, or the time it takes for one-half of a particular radioactive isotope in a sample to decay.
(ROOT (S (NP (DT The) (NN term) (NN half-life)) (VP (VBZ decribes) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NP (NN time)) (VP (VBN required) (PP (IN for) (NP (NP (NN half)) (PP (IN of) (NP (DT the) (JJ original) (NN material))))) (PP (TO to) (NP (NP (NN decay)) (PP (IN in) (NP (DT an) (NN isotope)))))))))) (. .)))