Harmodotron
(产生毫米波的)电子束管, (正交场)毫米波振荡管
🗣️ 情景例句
Something old.
旧的东西。
How much does packing take up of the total cost of the goods?
包装占货物总成本的百分比是多少？
We also played games on the sand.
我们还在沙滩上做游戏呢。