( ( ( ( ( Considerable ( frost ( this morning ) ) ) , ) and ) ( ( some ice ) ( formed ( on ( the river ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Considerable)) (VP (VBD frost) (NP (DT this) (NN morning)))) (, ,) (CC and) (S (NP (DT some) (NN ice)) (VP (VBD formed) (PP (IN on) (NP (DT the) (NN river))))) (. .)))
Considerable frost this morning, and some ice formed on the river.
(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))))) (. .)))