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
but they probably had other things on their minds.
但他们也许还有其他的事想要做。
Just the other way round.
正相反。
Hello, Ken.
你好，肯。