主动语态→被动语态:1、找到该句宾语(必须是在谓语动词后的),将它提到句子开头.2、用被动语态结构be+Vt过去分词构成句子.3、把原句的主语用by构成的介词短语带出,也可不加.eg:I finished my homework yesterday.→My homework was finished (by me) yesterday.特殊形式:1、部分Vi加上适当介词可当作Vt构成被动语态.eg:Parents look after their children carefully.→Children were looked after (by parents) carefully.2、联系动词没有被动语态.eg:The water feels warm.3、在主动语态中一些省略to的动词不定式改为被动语态时需加上to.eg:Teachers often make him stand outside.→He is often made to stand outside (by teachers).4、have、let等动词无被动语态.必要时,have可改为held,let sb to do sth可改为be allowed to do sth (被允许做某事).
主动语态转换成被动语态分三种情况:第一种句型:主语+谓语+宾语,主语与宾语交换位置。例如:I sent an email last night.昨天夜里我发了一封电子邮件。(主动结构)An email was sent (by me) last night.一封电子邮件昨天夜里(由我)发出了。(被动结构)第二种句型:主语+谓语+宾语+宾语,将其中任意一个宾语与主语交换位置。例如:My parents bought me a new computer.我的父母亲给我买了一台新电脑。(主动结构)A new computer was bought for me.有人给我买了一台新电脑。(被动结构)第三种句型:主语+谓语+复合宾语,将其中的宾语提到句首,而将宾语补足语仍留在原来的位置。例如:We found him lying under the tree.我们发现他躺在树底下。(主动结构,宾语补足语为现在分词。)