We sat in one of the upper tiers of the football stands. 我们坐在足球场看台的上层位置。
My wedding cake had four tiers, each supported by small pillars. 我的结婚蛋糕有4层，每层都由小柱子撑着。
I don't understand why you think we need yet another tier of management. 我不明白你为什么认为我们还需要一个管理层级。