( ( ( The source ) ( of ( virtually ( all freshwater ) ) ) ) ( ( is ( precipitation ( ( ( ( ( ( ( from ( the atmosphere ) ) , ) ( in ( ( the form ) ( of ( mist ( , ( ( rain and ) snow ) ) ) ) ) ) ) , ) ( as ( part ( of ( ( the ( water cycle ) ) ( over ( ( eons , ) millennia ) ) ) ) ) ) ) and ) ( in ( the ( present day ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN source)) (PP (IN of) (NP (RB virtually) (DT all) (NN freshwater)))) (VP (VBZ is) (VP (VBN precipitation) (PP (PP (IN from) (NP (DT the) (NN atmosphere))) (, ,) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NN mist) (, ,) (NN rain) (CC and) (NN snow))))) (, ,) (PP (IN as) (NP (NP (NN part)) (PP (IN of) (NP (NP (DT the) (NN water) (NN cycle)) (PP (IN over) (NP (NP (NNS eons)) (, ,) (NP (NN millennia)))))))) (CC and) (PP (IN in) (NP (DT the) (JJ present) (NN day)))))) (. .)))
The source of virtually all freshwater is precipitation from the atmosphere, in the form of mist, rain and snow, as part of the water cycle over eons, millennia and in the present day.
(ROOT (S (NP (DT The) (NN atmosphere)) (VP (VBZ is) (NP (NP (DT the) (NN source)) (PP (IN of) (NP (NN precipitation))))) (. .)))