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
And you gave up your career as a music teacher?
那么你就放弃了音乐教师的事业？
It seems he's disappointed.
看起来他好像很失望。
Oh, yes, I bought one, but I can't find it now.
噢，是，我买了票的，但现在找不见了！