tell me whoever is waiting to come in(为什么不是whomever）

tell me whoever is waiting to come in(为什么不是whomever） whomever ,whoever send to ----------,是whomever 还是whoever? whoever leaves the office should tell me 为什么不是be told 麻烦回答一些英语问题1.we wrote to __invited us.为什么用whoever而不是whomever? 关于whomever和whoever who,whoever,whom,whomever whoever与whomever who/whoever/whomever/whom 英语whomever与 whoever 英语 whoever whomever 区别 选whomever还是whoever?