现在完成时的被动语态结构是将have/has放在句首，然后加上be动词的相应形式。动作的执行者变为被动语态中的对象，并在动词后面加上by + 执行者的名称。当执行者无法确定时，可以省略by + 执行者的部分。例如，"I have finished my homework"可以转换为"My homework has been finished (by me)"。
而当我们需要将现在完成时转换为被动语态时，我们需要将 have/has 提到句子的前面，然后加上 be 动词的相应形式。例如，一般现在完成时的句子 "I have finished my homework" 可以被转换为被动语态结构 "My homework has been finished (by me)"。
需要注意的是，当我们将现在完成时转换为被动语态时，需要将动作的执行者（即主语）变为被动语态中的对象，并在动词后面加上 by + 执行者的名称。但是，当执行者无法确定时，我们可以省略 by + 执行者的部分。
以下是一些例子：
- 主动语态: They have cooked dinner.
- 被动语态: Dinner has been cooked (by them).
- 主动语态: She has finished the book.
- 被动语态: The book has been finished (by her).
- 主动语态: We have painted the walls.
- 被动语态: The walls have been painted (by us).
