Complex sentence: British Columbians were not able to buy liquor by the glass between 1921--1924 until a 1925 amendment of the "Government Liquor Act" allowed for the establishment of beer parlours.
Split into simpler sentences: British Columbians were not able to buy liquor by the glass between 1921 and 1924. A 1925 amendment of the "Government Liquor Act" allowed for the establishment of beer parlours.