Understrata
n. 底层 (understratum的变形)
🗣️ 情景例句
Don't litter.
请不要乱扔东西。
He left his home to look for employment.
他离家去找工作。
He informed the station at once, but no one there was able to explain the mystery.
他马上把情况报告了该基地，但那里的人没有一个能解释这到底是怎么回事。