Sffd
abbr. step-function frequency discriminator 阶跃函数鉴频器
🗣️ 情景例句
That's the back of Pete Waters's place.
那就是Pete Waters住处的后面。
To have money is a fear, not to have it a grief.
有钱使人担心，没钱使人伤心。
I'm tired of working all day.
整日工作使我厌烦。