Complex sentence: Khalidi earned his B.A from the American University of Beirut in 1939, and M.A. from the University of Michigan in 1940, and a PhD in history from Columbia University in 1955.
Split into simpler sentences: Khalidi earned his B.A from the American University of Beirut in 1939, and M.A. from the University of Michigan in 1940. He earned his PhD in history from Columbia University in 1955.