Gas-masks had been issued to everyone before they entered the danger zone. 在他們進入危險區之前，每人都發了防毒面具。
Any time you need to shout to be heard by someone near you, your hearing is most likely to be in a decibel danger zone. 任何時候你為了讓旁邊的人聽到你都需要大聲喊叫，這時候你的聽力都很可能處於一個分貝危險區。
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