sentence: Two scientist throws stones in the water while talking. sentence:  Scientist writes a formula on a board, then the scientists run and jumps in the water. sentence:  Then, people water ski in the water pulling by a boat. sentence:  A woman water ski while two men explains the movements made by the girl. sentence:  After, a man water ski holding a water sky rope tie to a pole while a person watch, then he falls in the water. sentence:  After, a person water ski and then falls in the water.