Echelons
n. （机构中的）等级, 阶层( echelon的复数形式 ); （军舰、士兵、飞机等的）梯形编队
🗣️ 情景例句
I am studying two majors, and it's quite a burden on my time.
我有两门主修课，这占据了我很大一部分时间。
That's a bad idea if I've ever heard one!
你出这什么馊主意！
There is a river in the picture.
画里面有一条河。