Sffd
abbr. step-function frequency discriminator 阶跃函数鉴频器
🗣️ 情景例句
Have a nice weekend.
周末快乐。
The timid child would not leave his mother's side.
那个胆小的孩子不愿离开母亲。
The girl, tears streaming down her face, begged to be allowed to slip into the guard's van.
女孩泪流满面，央求让她不声不响地到押车员车厢里去算了。