Complex sentence: She attended St Elphin's girls' boarding school in Darley Dale, Derbyshire, from 1920 to 1925, before becoming a teacher in elementary schools in impoverished mining areas of Nottinghamshire.
Split into simpler sentences: She attended St Elphin's girls' boarding school in Darley Dale, Derbyshire, from 1920 to 1925. In 1925, she became a teacher in elementary schools in impoverished mining areas of Nottinghamshire.