Must not do...
This indicates a prohibition of doing something.
예문
安全設備を外してはいけません。
You must not remove the safety equipment.
ここに立ってはいけません。
You must not stand here.
作業中に携帯電話を使ってはいけません。
You must not use your phone during work.
빠른 확인
작업 중에 휴대전화를 사용___はいけません。