情态动词被动语态的结构和例句具体解析如下：

1.表示现在

被动语态构成：情态动词 + be + 动词过去分词

The patient can be saved by him.

病人能够被他拯救。

A fire could be caused by the faulty operation.

错误操作可引起火灾。

She may be surprised by you.

你或许能给她惊喜。

The file must be checked by you.

你必须检查这份文件。

2.表示过去

被动语态构成：情态动词 + have been + 动词过去分词

A fire could have been caused by the faulty operation.

She may have been surprised by you.

The file must have been checked by you.

She should have been told by them.

以上就是情态动词被动语态的结构和例句，希望对你有所帮助。更多内容，可查看被动语态讲解