We use the same predicates to identify birthdays for this month and after today ; but we also use the min function to determine which is the next day this month that a birthday will fall on 我们使用相同的谓词来标识本月的所有生日和本月自今天起剩下的生日,但是另外用min ( )函数来确定本月接下来的哪一天有生日。