Collineation
直射（变换）, 同射变换
🗣️ 情景例句
But I have a doctor's appointment in the afternoon.
但我后天下午跟医生约好了。
What do you call this in English?
这个用英语怎么说？
Hurry up, Sam!The kettle's boiling!
快，萨姆。水开了！