b2输入公式：=if(c2>250,"严重污染",if(c2>200,"重度污染",if(c2>150,"中度污染",if(c2>100,"轻度污染",if(c2>51,"良","优")))))
公式如下：=LOOKUP(C2,{0,51,101,151,201,251},{"优","良","轻度","中度","重度","严重"})
