In the same year, the school set up "post school certificate classes, later known as "pre-university classes" to prepare students for tertiary education; the first batch of girl students were enrolled in ACS although students in the lower grades continued to be all male, a practice which persists to this day. Dr Thio Chan Bee, the first Asian principal of ACS, took over in 1952. During his tenure, both the Cairnhill and Barker Road premises expanded, in the latter's case through the building of Lee Hall, a three-storey building housing twelve classrooms and four laboratories.