Complex sentence: In 1939, after marrying her first husband, James Goble, Johnson left her teaching job and enrolled in a graduate math program, but quit after one year, having become pregnant and choosing to focus on her family.
Split into simpler sentences: In 1939, after marrying her first husband, James Goble, Johnson left her teaching job and enrolled in a graduate math program. She quit after one year, after becoming pregnant and choosing to focus on her family.