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' 。
Knowing that the industrious ant lives in a highly organized society does nothing to prevent us from being filled with revulsion when we find hordes of them crawling over a carefully prepared picnic lunch.
即使知道勤奋的蚂蚁生活具有高度组织性的社会里,当看到大群蚂蚁在我们精心准备的午间野餐上爬行时,我们也无法抑制对它们的反感。