一般现在时: am / is / are done 一般过去时: was / were done 现在进行时: am / is / are being done 过去进行时: was / were being done 现在完成时: have / has been done 过去完成时: had been done 一般将来时: shall / will be done ; be going to be done 当句中含有情态动词时,句子结构为 can / must / have to…be done