Quadric
a. 二次的\\nn. 二次曲面
🗣️ 情景例句
Whose woods these are I think I know.
这是谁的林子， 我想我知道。
Missing school to watch the football match is out of the question.
为看足球赛而旷课，那可不行。
Yes, they are.
对，这些是英语书。