must have been done是什么被动语态

must have been done是什么被动语态 have been done 是被动语态 have sth done 也是被动语态 我有点蒙了. 被动语态be done中 be是什么词性?还有现在完成时的被动语态have been done 中have been是什 完成时被动语态为什么是have been done have/has been done 是现在完成的被动语态 MUST have been done must have been done must have done 问下被动语态问题,have been done 是现在完成时的被动语态,那we have done this homew must have been done/must be done must have done和must be在处于被动语态时的区别 含有be动词的被动语态怎么变,have been done一定指被动吗 have done和 have been的区分 有些情况写 have been未必是被动语态啊