四、主动语态变被动语态的方法

1 把主动语态的宾语变为被动语态的主语。

2 把谓语变成被动结构(be+过去分词)，根据被动语态句子里的主语的人称和数，以及原来主 动语态句子中动词的时态来决定be的形式。

3 把主动语态中的主语放在介词by之后作宾语，将主格改为宾格。例如：

1) All the people laughed at him.= He was laughed at by all people.

2) They make the bikes in the factory.= The bikes are made?by them?in the factory.

记忆歌诀：宾变主，主变宾，by短语后面跟。谓语动词变被动，be后“过分”来使用。

五、含有情态动词的被动语态

含有情态动词的主动句变成被动句时，由“情态动词+be+过去分词”构成，原来带to的情态动词变成被动语态后“to”仍要保留。

记忆歌诀：情态动词变动，情态加be加“过分”，原来带to要保留。例如：

1) We can repair this watch in two days. = This watch can be repaired in two days.

2) You ought to take it away. = It ought to be taken away.

3) They should do it at once. = It should be done at once

以上是高三英语被动语态知识点讲解，以供参考学习。