( ( ( Frost - ) ( ( Ice crystals ) ( that ( ( form ( on ( grass ( and ( other objects ) ) ) ) ) ( when ( ( the ( temperature ( and ( dew point ) ) ) ) ( fall ( below freezing ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NNP Frost)) (: -) (NP (NP (NN Ice) (NNS crystals)) (SBAR (WHNP (WDT that)) (S (VP (VBP form) (PP (IN on) (NP (NN grass) (CC and) (JJ other) (NNS objects))) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN temperature) (CC and) (NN dew) (NN point)) (VP (VBP fall) (PP (IN below) (NP (NN freezing)))))))))) (. .)))
Frost- Ice crystals that form on grass and other objects when the temperature and dew point fall below freezing.
(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))))) (. .)))