Quadtrees
四元树
🗣️ 情景例句
I like to listen to the music and to play piano and occasionally to go swimming.
我喜欢听音乐、弹钢琴，有时候去游泳。
Keep it down!
别闹了！
He was caught, put in chains, and sent to America as a slave.
他被抓住了，带上镣铐，送到美国当奴隶。