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
What do you like to do during holiday?
在假日你喜欢做什么？
Music is his chief hobby.
音乐是他的主要业余爱好。
Really? Which ones?
真的吗？哪种工作呢？