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' 。
But my father had described over and over again what we should see at every milestone, after leaving the nearest town,
而是父亲曾详细给我讲了,在过了离故乡最近的那个小镇后,在每一个路标处可见到些什么。