你應該知道的事

YSK-如果你聽到鈴聲或來自封閉的電梯或井道的蜂鳴聲,你應該打電話尋求幫助。
YSK- If you hear a bell ringing or a beeping from an closed elevator or shaft, you should call for help.
from /r/YouShouldKnow