Extremal
[计] 极值曲线
🗣️ 情景例句
He met his girfriend throught a public chat room.
他是在一个公共聊天室里认识他女友的。
He can't come and he sends his apologies.
他为他的不能前来致歉。
I don't know. My head hurts.
不知道。我头痛。