一个是现在完成时,一个是过去完成时
he has been worked in hospital
表示他过去在医院工作,现在有可能还在医院工作
单数或第三人称时用has
they have been worked in hospital
人称复指,第一二人称时用have
he had been worked in hospital
他过去在医院工作,现在不在了