Sffd
abbr. step-function frequency discriminator 阶跃函数鉴频器
🗣️ 情景例句
When people stand together, no one can stop them.
当人们门到一起的时候，就没有人可以阻止他们相互谈论。
Please lend an ear to this man's important news.
请注意倾听有关这个男人的重大新闻。
But wouldn't you like to spend an extra day or two here?
你们不愿意在北京多待一天吗？