Complex sentence: In 1956, Mowat won the Governor General's Award and in 1957, the Book of the Year Award, Canadian Association of Children's Librarians, for "Lost in the Barrens".
Split into simpler sentences: In 1956, Mowat won the Governor General's Award. And in 1957, the Book of the Year Award, Canadian Association of Children's Librarians, for "Lost in the Barrens".