may have been done是什么时态

　　have been done的用法：

　　have been done是现在完成时的被动语态结构。被动语态完整结构：肯定式为：have/has+been+done。否定式为：have/has+not+been+done。现在完成时是“过去的动作或状态持续到现在并且已经完成”。

　　have been done的例句：

　　1、A lot of good deeds have been done by him. 他做了很多好事。

　　2、These projects have been finished already. 这些项目已经完成。

　　3、The work had not been done very thoroughly.这工作做得不太认真。

　　4、They saw the job had been done.他们看到工作已经做了。

　　5、She knew it would be difficult to undo the damage that had been done.她知道想要消除已经造成的损害是很难的。

　　6、He was angry at finding that nothing had been done. 当他知道没有啥事做出来生起气来。