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' 。
In place of the great trees which had been growing there for centuries patches of green had begun to appear in the blackened soil.
一片片的绿草开始出现在这片烧焦的土地上,代替了多少世纪以来一直生长在那里的参天大树。