EXCEL里设到期前自动提醒的公式？

各位大神，帮忙在EXCEL里设个公式可以吗？我管的杂事比较多，怕忘记了，然后想在EXCEL里做一个提醒表。比如 I=开始日期，K=多久到期，L=提前多少天提醒。 我设的公式如下，但总是结果不对，实在没辙了，求职大神帮忙，谢谢。IF(I2"",IF(OR(AND(YEAR(I2)+K2=YEAR(NOW()),MONTH(NOW())=MONTH(I2),DAY(NOW()+L2)=DAY(I2)),AND(YEAR(I2)+K2=YEAR(NOW()),MONTH(NOW())MONTH(I2),DAY(NOW()+L2)DAY(I2))),"即将到期",IF(OR(AND(YEAR(I2)+K2=YEAR(NOW()),MONTH(NOW())=MONTH(I2),DAY(NOW())DAY(I2)),AND(YEAR(I2)+K2=YEAR(NOW()),MONTH(NOW())MONTH(I2)),YEAR(I2)+K2YEAR(NOW())),"已经过期","还未过期")))