( Sleet ( ( happens ( when ( ( the ( air temperature ) ) ( is ( ( ( ( above ( freezing ( near ( ( ( the clouds ) , ) ( where ( ( the rain ) ( is formed ) ) ) ) ) ) ) , ) and ) ( below ( freezing ( near ( ( the surface ) ( of ( the earth ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Sleet)) (VP (VBZ happens) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN air) (NN temperature)) (VP (VBZ is) (PP (PP (IN above) (NP (NP (NN freezing)) (PP (IN near) (NP (NP (DT the) (NNS clouds)) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (NN rain)) (VP (VBZ is) (VP (VBN formed))))))))) (, ,) (CC and) (PP (IN below) (NP (NP (NN freezing)) (PP (IN near) (NP (NP (DT the) (NN surface)) (PP (IN of) (NP (DT the) (NN earth)))))))))))) (. .)))
Sleet happens when the air temperature is above freezing near the clouds, where the rain is formed, and below freezing near the surface of the earth.
(ROOT (S (NP (NP (JJS Most)) (PP (IN of) (NP (NP (DT the) (NN earth) (POS 's)) (NN freshwater)))) (VP (VBZ is) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (ADJP (JJ frozen)))))) (. .)))