?? 詞語組成解析
sir
[s?]
n. 先生;（用于姓名前）爵士;（中小學生對男教師的稱呼）先生;老師;
??? 情景例句
Don't litter.
請不要亂扔東西。
To commute to work
上班工作
He was in car number fifteen.Five other cars were just behind him.
他在第15號車里，其他5輛汽車跟在他后面。