was done是一般过去时，done这个过去分词在这里用做形容词，表示“一个事情完成了”这样一个状态；
have done是现在完成时，had done是过去完成时。
双语例句
1、The work was done with the minimum amount of effort.
做这项工作没费什么劲。
2、The work was done according to her instructions.
这项工作是依照她的`指示办的。
3、It was done without the principal's authority.
做这件事未经校长批准。
4、None of the work was done.
那些工作全都未干。
5、What beats me is how it was done so quickly.
使我困惑不解的是，这事怎么这么快就完成了。
温馨提示：
