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' 。
The whole village has been working day and night gathering and threshing this year's crop before the September rains.
全村的人都日夜奋战,要赶在9月的雨季之前把今年的庄稼收获上来,打完场。