decimate
/ˈdesɪmeɪt; `dɛsəˌmet/ v[Tn]
(a) kill or destroy a large part of (sth) 杀死或毁坏（某物）之大部
Disease has decimated the population. 疾病使大部分人死亡.
(b) (infml 口) reduce (sth) considerably 相当程度地减少、 降低（某事物）
Student numbers have been decimated by cuts in grants. 助学金削减後, 学生人数大大减少.