Complex sentence: As a child, she lived there for 11 years before she moved to Dundee as a result of Mr. Slessor's drinking problem, and being the second child of seven, Mary had suffered more from her father's drinking than the other children.
Split into simpler sentences: As a child, she lived there for 11 years before she moved to Dundee. The move to Dundee was a result of Mr. Slessor's drinking problem, and being the second child of seven, Mary had suffered more from her father's drinking than the other children.