1.Teenagers 1.Teenagers should be allowedshould be allowed to choose to choose their own clothes.their own clothes.2.English 2.English is spokenis spoken by many people . by many people .3.Trees 3.Trees are plantedare planted in South China. in South China. 语态：表示语态：表示主语主语和和谓语动词谓语动词之间的关系。之间的关系。英语有英语有两种语态两种语态，即，即主动语态主动语态和和被动语态被动语态。。 主动语态：表示主语是动作的执行者。被动语态：表示主语是动作的承受者。语态语态 1.1. 把主动语态的把主动语态的宾语宾语变为被动语态的变为被动语态的主语主语。。2.2. 把主动语态的把主动语态的谓语谓语变为被动语态的变为被动语态的谓语谓语。。3.3. 把主动语态的主语变为被动语态的把主动语态的主语变为被动语态的 byby 短语。（短语。（①① byby 短语可以省略。短语可以省略。② ② byby 短语短语 后跟代词的宾格。）后跟代词的宾格。）by him.He often He often asksasks math teacher questions. math teacher questions.Math teacher is often asked questions 被动语态的被动语态的时态时态是由是由 bebe 的时态的时态决定的，决定的， bebe 是什么时态，全句就是什么是什么时态，全句就是什么时态，时态， bebe 动词后面的过去分词不变。动词后面的过去分词不变。 is/am/are+ V 过去分词1. 一般现在时的被动语态结构： 1. They play football on Sunday.2.Lucy does the homework in the evening.Football is played by them on Sunday.The homework is done by Lucy in the evening. 一般过去时的被动语态结构：was/were + 过去分词last year.WeWe plantedplanted many trees many trees last year.last year.Many trees were planted 1. They built the tall building last year.2. He took good care of his little brother yesterday.The tall building was built by them last year.His little brother was taken good care of by him yesterday. 一般将来时的被动语态结构：will be+ 过去分词They will finish the work in ten days.by them in ten days.The work will be finished 1.We will have a ...
