Particle number density
[化] 平均密度
🧩 词语组成解析
🗣️ 情景例句
I still don't understand what you mean.
我还是弄不懂你是什么意思。
Ignorance is the mother of impudence.
厚颜无耻由于愚昧无知。
The children were leaving school on Tuesday when they saw a truck.
星期二，孩子们正放学回家，这时，他们看见一辆卡车。