Complex sentence: At this point the high school section was separated from the College, and in September, 1950, St. Michael's College School opened its doors in a new building at Bathurst Street and St. Clair Avenue, where it is situated today.
Split into simpler sentences: At this point the high school section was separated from the College. In September 1950, St. Michael's College School opened its doors in a new building at Bathurst Street and St. Clair Avenue, where it is situated today.