Sffd
abbr. step-function frequency discriminator 阶跃函数鉴频器
🗣️ 情景例句
How nice to meet you.
认识你真高兴。
He that once deceives is ever suspected.
骗人一次，受疑一世。
One young calf especially enjoyed raising a turtle to the surface with his snout and then shoving him across the tank like an aquaplane.
一只小海豚特别喜欢用鼻子把海龟推到水面，然后像滑水板一样把海龟从水池的这一边推到那一边。