( Then ( ( at ( ( the end ) ( of summer ) ) ) ( , ( ( the cycle ) ( ( repeats itself ) . ) ) ) ) )
(ROOT (S (RB Then) (PP (IN at) (NP (NP (DT the) (NN end)) (PP (IN of) (NP (NN summer))))) (, ,) (NP (DT the) (NN cycle)) (VP (VBZ repeats) (NP (PRP itself))) (. .)))
Then at the end of summer, the cycle repeats itself.
(ROOT (S (NP (DT The) (NN water) (NN cycle)) (VP (VBZ ends) (SBAR (IN with) (S (NP (PRP it)) (VP (VBZ repeats) (NP (PRP itself)))))) (. .)))
The water cycle ends with it repeats itself.