context: As early as the late 1820s and early 1830s, she and her sister began opening infant schools in northeastern Ohio.
source: After obtaining a degree from Oberlin College in 1840s, Cowles began a formal career as a teacher.
reference_original: После получения степени в Оберлин-колледже в 1840-х годах Коулз начала официальную карьеру учителя.
reference_flipped: После получения степени в Оберлин-колледже в 1840-х годах Коулз начал официальную карьеру учителя.