=IF(K14>=1,"A",IF(AND(0.9<=K14,K14<1),"B",IF(AND(0.8<=K14,K14<0.9),"C",IF(AND(0.7<=K14,K14<0.8),"D",IF(AND(0.6<=K14,K14<0.7),"E","小于0.6")))))
如果是区间数值，需要用and，不能直接连起来。
