sentence: People walk holding surfboards, then they board a boat. sentence:  A man water ski behind the boat jumping high and spinning. sentence:  Then, a woman and a man water ski doing acrobatic jumps. sentence:  A boat sails empty in the river. sentence:  After, men water ski jumping and turning around. sentence:  Next, a person surf on the waves created by the boat, after the man water ski jumping and flipping high.