同学你好，该知识点来自沪江网校《英语零基础直达大学六级【听说升级版 随到随学班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
何时运用被动语态：

（1）强调动作的接受者：America was discovered by Columbus. 美洲是哥伦布发现的。
（2）不知谁是动作的执行者：You are wanted on the phone.有你的电话。
（3）作客观说明：It is said that the meeting has been put off. 据说会议推迟了。


主动变被动的基本方法：

（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.

过    去  did→was / were + done
They built the bridge in 1980.
→The bridge was built in 1980.

将    来  will/shall do → will/shall + be + done
He will read the book tomorrow.
→The book will be read tomorrow.

现在完成  have/has done → have/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  will/shall have done → will/shall 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/is/are doing → am/is/are + being + done
They are drawing the picture.
→The picture is being drawn by them.< /p>

过去进行  was/were doing → was/were + being + done
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.

祝同学学习进步~