Complex sentence: There Midlo Hall completed her B.A. and master's degree, before returning to the US in 1964 and in 1966 she started her graduate studies to earn her doctorate at the University of Michigan.
Split into simpler sentences: There Midlo Hall completed her B.A. and master's degree, before returning to the US in 1964. In 1966 she started her graduate studies to earn her doctorate at the University of Michigan.