Pdu
[计] 协议数据单元
🗣️ 情景例句
How many classes are you taking this semester?
这学期你有多少课？
Laugh at your ills, And save doctors' bills.
生病不忧虑，节省医药费。
If we could actually see the path described by a particle,such as a sand grain in the rock,
假如我们真能看到的运动轨迹，诸如岩石中一个沙粒分子