Complex sentence: In high school he attended Carrabassett Valley Academy and was a nationally ranked snowboarder, some of his sponsors included Arbor Snowboards, Smith Optics, Adidas, Giro, and Swix.
Split into simpler sentences: In high school he attended Carrabassett Valley Academy and was a nationally ranked snowboarder. Some of his sponsors included Arbor Snowboards, Smith Optics, Adidas, Giro, and Swix.