BC
adverb uk/ˌbiːˈsiː/ us/ˌbiːˈsiː/
公元前（Before Christ的缩写）
abbreviation for Before Christ: used in the Christian calendar when referring to a year before Jesus Christ was born
The Battle of Actium took place in 31 BC. 阿克提尔姆战争爆发于公元前31年。
Compare: AD adverb (CALENDAR)BCE