Ofda
abbr. 美国对外灾难援助办公室
🗣️ 情景例句
I think I have fallen in love with someone.
我恋爱了。
We can't recall how often he's written.
我们记不起来他每隔多久写一封信。
It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951;
这个频率是空间氢原子释放的自然频率，是在1951年被人类发现的。