If you don't know a person's last name, use 'ma'am' or 'sir'.
如果你不知道一人的姓, 你应称呼他为 'ma'am' 或 'sir' 。
No, I couldn't do that. Everybody else will be wearing jewellery. I can't be the only woman who isn't wearing jewellery.
不,我不能戴花。别的人都戴首饰,唯有我一个人不戴首饰,这怎么能行呢?