Passive air defense
un. 消极防空
🧩 词语组成解析
air
[ɛə]
n. 天空;气氛;空运;（简单易记的）曲调;
vt.& vi. 晾晒;烘干;播送;广播;
vt. 使房间通风， 透气;
🗣️ 情景例句
Think about the word and use it, in your mind, in a sentence.
想想这个字，然后去用它，在脑子里，在句子里。
All of us hope that you will enjoy yourselves.
我们全体人员祝大家过得愉快。
Yes, and we must stop people walking on this floor until it's firm. It may be necessary to put up a notice saying Keep off. Another thing, we' ll have to drill a hole in the wall for the electric wires.
是的，因此在地板牢固前，我们必须防止人们从地板上行走。可能还需要竖一个布告牌，写上“不得践踏”。还有，我们必须在墙上钻一个电线孔。