Complex sentence: Kirby's Pig Stand was America's first drive-in restaurant, opened by Jessie G. Kirby and Reuben Jackson in 1921, in Dallas, Texas.
Split into simpler sentences: Kirby's Pig Stand was the first drive-in restaurant to open in the United States. It was opened by Jessie G. Kirby and Reuben Jackson in 1921, in Dallas, Texas.