Quadtree
[计] 四树, 四叉树
🗣️ 情景例句
OK, what do you need most of all?
好， 你们最需要的是什么？
One may sooner fall than rise.
跌倒容易爬起难。
An even harder situation is to be on the platform in good time for a train and still to see it go off without you.
更难堪的情况是虽然及时赶到站台上，却眼睁睁地看着那趟火车启动，把你抛下。