标题: 词汇与表达：tier [打印本页] 作者: etthink 时间: 2023-1-6 03:44 标题: 词汇与表达：tier tier[tɪə(r)] A tier is a row or layer of something that has other layers above or below it.A tier is a level in an organization or system.
Study on the three tiers military operation of modern air defense system
现代防空体系中三层作战问题研究