英语被动语态通过在主语后加上助动词"be"和过去分词来构成，变化规则包括现在时(am/is/are + 过去分词)，过去时(was/were + 过去分词)，现在完成时(have/has been + 过去分词)，和过去完成时(had been + 过去分词)。掌握这些规则可以帮助我们更好地理解和使用英语被动语态。
现在时被动语态
- am/is/are + 过去分词
例如：
- The book is written by him.（这本书是他写的。）
- The letter is being typed by her.（这封信正在被她打字。）
过去时被动语态
- was/were + 过去分词
例如：
- The car was repaired by him.（这辆车被他修好了。）
- The report was being read by her when I arrived.（我到达时，她正在看那份报告。）
现在完成时被动语态
- have/has been + 过去分词
例如：
- The project has been completed by them.（这个项目已经被他们完成了。）
- The house has been being built for a year.（这座房子已经建了一年了。）
过去完成时被动语态
- had been + 过去分词
例如：
- The work had been done before he came back.（他回来之前这项工作已经完成了。）
- The food had been being cooked for two hours before it was ready.（这食物准备了两个小时才好。）
