Quadric
a. 二次的\\nn. 二次曲面
🗣️ 情景例句
Did you know I can type almost 60 words per minuter?
你知道吗，我能每分钟打60个字。
And she?
她呢？
and it is only in the seas and rivers, and sometimes lakes, where mud and sit have been continuously deposited,
所以只有在泥沙不停淤积的海洋和江河里，有时在湖泊里，