1.何时运用被动语态：

(1)强调动作的接受者：America was discovered by Columbus.

(2)不知谁是动作的执行者：You are wanted on the phone.

(3)作客观说明：It is said that the meeting has been put off.(经典句型)

2.主动变被动的基本方法：(说起来容易，掌握起来需要用心!)

(1)主动语态中的宾语变为被动语态的主语。

(2)谓语动词变为由“be + 过去分词”的形式，配合时态作相应变化。

(3)主动语态主语置于介词 by之后，如无必需，则省略。

(4)不及物动词没有被动语态。

现 在 do (does) →am / is / are + done

We keep the piano in the living-room.

→The piano is kept in the living-room.新概念作文

过 去 did→was / were + done

They built the bridge in 1980.

→The bridge was built in 1980.

将 来 shall shall

will do → will + be + done

He will read the book tomorrow.

→The book will be read tomorrow.

现在完成 have have

has done → has + been + done

We have delivered the newspaper.

→The newspapers have been delivered (by us).

过去完成 had done → had been done

She had seen the film before she came here.

→The film had been seen before she came here.

将来完成 shall shall

will have done → will have + been + done

By the end of this term we shall have finished 80 texts.

→By the end of this term 80 texts will have been finished.

现在进行 am am

is doing → is + being + done

are are

They are drawing the picture.

→The picture is being drawn by them.

过去进行 was doing → was + being + done

were were

He was reviewing their lessons at this moment yesterday.

→Their lessons were being reviewed at this moment yesterday.

情态动词 may may

can can

must must

should do → should + be + done

ought to ought to

used to used to

You must write an article on the subject.

→An article must be written on the subject.