Preorder traversal
[计] 前序遍历
🧩 词语组成解析
[计] 先根次序
[计] 遍历
🗣️ 情景例句
Bye.
再见。
I can paint.
我会画。
my aunt unexpectedly returned one afternoon with a party of guests and instructed Bessie to prepare dinner.
一天下午，她出其不意地回来了，带来一大批客人，吩咐贝西准备晚饭。