将主动语态改为被动语态有哪些方法

1、将主动语态改为被动语态要注意三个方面：1，主动语态的宾语改为被动语态的主语；2，主动语态的谓语动词改为Be+过去分词；3，将主动语态的主语改为介词by之后的宾语，放在谓语动词之后，有时可省略

3、不带to的动词不定式作宾语补足语的主动语态，改为被动语态时不定式前要加to，如they watched the children sing that morning改为被动为the children were watched to sing that morning

5、短语动词是不可分割的整体，改为被动语态时要保持其完整性，不可遗漏介词或副词，如we must take good care of the young trees改为被动为the young trees must be taken good care of