( ( ( Slows down ) ( ( ( ( ( the ( ( velocity or ) speed ) ) ( of ( ( the water ) ( flowing ( into ( the river ) ) ) ) ) ) , ) thus ) ( decreasing erosion ) ) ) ; )
(ROOT (S (VP (VB Slows) (PRT (RP down)) (NP (NP (NP (DT the) (NN velocity) (CC or) (NN speed)) (PP (IN of) (NP (NP (DT the) (NN water)) (VP (VBG flowing) (PP (IN into) (NP (DT the) (NN river))))))) (, ,) (RB thus) (NP (VBG decreasing) (NN erosion)))) (: ;)))
Slows down the velocity or speed of the water flowing into the river, thus decreasing erosion;
(ROOT (S (PP (IN As) (NP (NP (DT the) (NN temperature)) (PP (IN of) (NP (NN water) (NNS decreases))))) (, ,) (NP (DT the) (NN water) (NNS molecules)) (VP (VB slow) (PRT (RP down))) (. .)))