Quadric
a. 二次的\\nn. 二次曲面
🗣️ 情景例句
As far as possible, the teacher should expose the student to real life situations.
教师应该尽可能使学生接触现实生活的情景。
Where'd you come from?
你从哪冒出来的啊？
Because it's winter now. The weather here is very cold in winter, isn't it?
因为现在是冬天。这儿的冬天天气非常冷，对吗？