( ( FROST ( ( ( A covering ) ( of ( small ( ice crystals ) ) ) ) ( that ( ( forms ( ( ( on or ) near ) ( the ground ) ) ) ( when ( temperatures ( ( ( approach or ) drop ) ( below 32 ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB FROST) (NP (NP (DT A) (NN covering)) (PP (IN of) (NP (JJ small) (NN ice) (NNS crystals))) (SBAR (WHNP (WDT that)) (S (VP (VBZ forms) (PP (IN on) (CC or) (IN near) (NP (DT the) (NN ground))) (SBAR (WHADVP (WRB when)) (S (NP (NNS temperatures)) (VP (VBP approach) (CC or) (VBP drop) (PP (IN below) (NP (CD 32))))))))))) (. .)))
FROST A covering of small ice crystals that forms on or near the ground when temperatures approach or drop below 32.
(ROOT (S (NP (NP (DT The) (NN ice) (NNS crystals)) (SBAR (WHNP (WDT that)) (S (VP (VBP form) (PP (IN on) (NP (DT the) (NN ground))))))) (VP (VBP are) (VP (VBN called) (S (ADJP (JJ frost))))) (. .)))