Complex sentence: Clemente Martinez Perez was born in El Paso, Texas, March 17,1909, and resided in the United States until 1919 or 1920 when his parents took him to Mexico.
Split into simpler sentences: Clemente Martinez Perez was born in El Paso, Texas, on March 17,1909. He resided in the United States until 1919 or 1920, when his parents took him to Mexico.