But none of them has been turned to stone yet这句话中为什么用has?

But none of them has been turned to stone yet这句话中为什么用has? But none of them has been turned to stone yet!这句话里none of在这里 but none of them has been turned to stone yet.翻译出到目前为止是因为完成时 新概念二 时态问题第28课 but none of them has been turned to stone yet! --------of them has been turned to stone yet.这是新概念英语2里的一个课后题 "One of them has __engineer."中为什么要填turned而不是been、become、got None of them has come back yet.与None of them have come back -___ these books ___well?-No,none of them has sold out yet. Neither of us has been to Beijing.为什么用has jenny promised to come early but she has not（ turned up ）yet 用...has/have already been...but...not...yet.造句 no.none of us has been abroad.