Pfs
abbr. porous friction surface(d) 渗透摩擦面
🗣️ 情景例句
I wonder whether I might ask you a question.
我是否可以问你一个问题？
Eagles fly alone, but sheep flock together.
鹰单飞，羊群集。
He suggested that a double railway-tunnel should be built.
他提议建一条双轨隧道，这样就解决了通风问题。