语法
一、被动句的结构：
be的变位 + 动词过去分词 + by + 动作执行者
二、基本句型变换
2.1、主语 + 谓语 + 宾语
The rabbit ate the carrot
The carrot was eaten by the rabbit
很多情况下，无需表明 “被谁”这个概念
A carrot was eaten
2.2、主语 + 谓语 + 直接宾语 + 间接宾语
The rabbit gave the carrot to the wolf.
The wolf was given the carrot by the rabbit.
The carrot was given to the wolf by the rabbit.
将句子转换成主动语态的：主语 + 谓语 + 间接宾语 + 直接宾语
? The rabbit gave the wolf the carrot
2.3、主语 + 谓语 + 宾语 + 宾语补语
The wolf invited the rabbit to her party.
The rabbit was invited to the party by the wolf.
省略 to 的不定式做宾语补语在转换成被动语态时要还原 to
The rabbit made the wolf laugh. 这里laugh 是省略 to 的不定式做宾语补语
The wolf was made to laugh by the rabbit
三、被动语态和时态、语气、助动词结合：
