stratum use层级使用stratumn.地层；阶层stratum consistency地层分层一致性Stratum ventilation层式通风stratum gelatinosum胶质层(嗅叶)stratum of a society社会阶层stratum subvasculare血管下层, 粘膜下层stratum functionalis[子宫内膜]功能层stratum distributing地层分布stratum distribution地层分布Stratum relationship阶层关系stratum germinativum马尔皮基氏层,生发层