Acn
abbr. Automatic Celestial Navigation 自动天体导航\\nabbr. 乙腈
🗣️ 情景例句
Hi, Michelle.
嗨， Michelle。
Much better.
好多了。
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。