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' 。
However, he had at last been allowed to send a fax in which he informed the editor that the he had been arrested while counting the 1,084 steps leading to the fifteen-foot wall which surrounded the president's palace.
不过,他终于获准发回了一份传真。在传真中他告诉编辑,就在他数通向15英尺高的总统府围墙的1,084级台阶时,被抓了起来。