kill something off
phrasal verb with kill verb uk/kɪl/ us/kɪl/
灭绝；杀光
to destroy something completely, usually over a period of time
The use of pesticides is killing off birds and fish. 杀虫剂的使用将使鸟类和鱼类灭绝。
figurative Lack of funding is killing off small theatres. 缺乏资金使小剧院纷纷倒闭。