Hfo
abbr. heavy fuel oil 重（燃）油; high-frequency oscillator 高频振荡器
🗣️ 情景例句
It's certainly a pleasure to meet you.
认识你真是我的荣幸。
If he doesn't pay, who will?
如果他不，谁要付账？
I'm not sure that we can wait that long.
我不知道我们是否能够等那么久。