( ( ( Decay curve ) ( of ( ( a ( radioactive element ) ) ( with ( a half-life ) ) ) ) ) ( ( equal ( to ( one ( time unit ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Decay) (NN curve)) (PP (IN of) (NP (NP (DT a) (JJ radioactive) (NN element)) (PP (IN with) (NP (DT a) (NN half-life)))))) (VP (VBP equal) (PP (TO to) (NP (CD one) (NN time) (NN unit)))) (. .)))
Decay curve of a radioactive element with a half-life equal to one time unit.
(ROOT (S (NP (DT The) (NN decay) (NN rate)) (VP (VBZ is) (VP (VBN measured) (PP (IN in) (NP (NP (DT a) (NN unit)) (VP (VBN called) (NP (DT the) (NN half-life))))))) (. .)))