n.等级( tier的名词复数 );包扎的人;一排高过前面一排的东西;阶梯座位的一排;
例句:
The sail is fastened to the yard with tiers.
船帆用系绳紧紧绑在帆桁上.
The structure of the Earth as eggs, can be divided into three tiers.
地球的结构就象鸡蛋, 可分为三层.
There are three different tiers of initials in Diocots.
在双子叶植物中有三层不同的原始细胞.