( ( In winter ) ( ( the sea ) ( ( becomes ( ( more saline ) ( as ( freshwater ( freezes ( to ( form ( sea ice ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (NN winter))) (NP (DT the) (NN sea)) (VP (VBZ becomes) (ADJP (ADJP (RBR more) (JJ saline)) (SBAR (IN as) (S (NP (NN freshwater)) (VP (VBZ freezes) (S (VP (TO to) (VP (VB form) (NP (NN sea) (NN ice)))))))))) (. .)))
In winter the sea becomes more saline as freshwater freezes to form sea ice.
(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)))))) (. .)))