( ( The sun ) ( ( ( ( brightens and ) fades ) ( over ( ( ( the ( sunspot cycle ) ) , ) ( the ( 11-year cycle ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ brightens) (CC and) (VBZ fades) (PP (IN over) (NP (NP (DT the) (JJ sunspot) (NN cycle)) (, ,) (NP (DT the) (JJ 11-year) (NN cycle))))) (. .)))
The sun brightens and fades over the sunspot cycle, the 11-year cycle.
(ROOT (S (NP (NNS Sunspots)) (VP (VBP occur) (PP (IN in) (NP (DT a) (CD 11) (NN year) (NN cycle)))) (. .)))