英语动词有主动和被动两种语态。主动语态表示主语是动作的执行者,又叫施动者;被动语态表示主语是动作的承受者，又叫受动者。区分主动语态和被动语态，主要看主语是执行者还是承受者。如：
The flowers and grass should be watered.(____语态)
We should water the flowers and grass.(____语态)
◆一 构成
1.被动语态是由“助动词 be+过去分词”构成的，助动词 be有时态、人称和数的变化。 Tom broke the cup.(主动语态)→ The cup was broken by Tom.(被动语态)
2.被动语态有以下 8种：
一般现在时： be( am/ is are)+过去分词 Trees are planted in spring.
一般过去时： be( was/ were)+过去分词 The house was built last year.
现在进行时： be( am/ is are)+ being+过去分词 The car is being repaired.
过去进行时： be( was/ were)+ being+过去分词
现在完成时： have/ has+ been+过去分词 The light has been turned off.
过去完成时： had+ been+过去分词
一般将来时： will be+过去分词 Lei Feng will be remembered by us forever.
含情态动词的：情态动词+ be+过去分词 My homework can be finished in two hours.
3.被动语态常用于以下场合：
①不知道或没有必要说明动作的执行者是谁时。如： My bike was stolen yesterday.我的自行车昨天被偷了。
②强调动作的执行者时，使用“ by+动作的执行者”。如： The pen was used by my father.这支钢笔是我父亲用过的。
※只有及物动词才有被动形式，不及物动词如 rise/ come/ go/ take/ place/ happen等，没有被动形式。
◆二 主动语态变被动语态的步骤
通常遵循以下三个步骤：
1. 把主动语态的宾语变成被动语态的主语。
2. 把主动语态的谓语动词变为与其时态相对应的被动形式，且与被动语态的主语保持人称和数的一致。
3. 将主动语态的主语变为介词 by的宾语，置于句末。“ by+宾语”在句中常省略。
主动语态： Many people speak English. 这里还需要连线
被动语态： English. is spoken by many people.
如： Lu Xun wrote this book.→ This book was written by Lu Xun.这本书是鲁迅写的。
People are cutting down many trees now.→ Many trees are being cut down now.现在许多树正被砍伐。
◆三 主动语态和被动语态的转换
1.双宾语的被动形式
双宾语的句子在变为被动语态时，有两种变法：
① 如果把指人的间接宾语变为主语，那么指物的直接宾语保留不动。如： His teacher gave him a book.→ He was given a book by his teacher. He has bought me a present.→ I have been bought a present.
②如果要将指物的直接宾语变为主语，那么动词后要用介词 to/ for，这个介词是由与其搭配的动词决定的。如： His teacher gave him a book.→ A book was given to him by his teacher. He has bought me a present.→ A present has been bought for me.
※常见的能接双宾语的动词有 give/ show/ bring/ lend/ send等，这些词与介词 to搭配; buy/ make/ draw等，这些词与介词 for搭配。
2.动词短语的被动语态
许多不及物动词加上介词或副词后构成的短语动词相当于及物动词，是一个不可分割的整体，在变为被动语态时不能把短语动词分开，也不能漏掉短语动词中的介词或副词。 如：
① We should speak to old men politely.→ Old men should be spoken to politely.
② He always takes care of his sister.→ His sister is always taken care of( by him).
③ She turned off the radio.→ The radio was turned off( by her).
3. 省略的 to动词不定式用于被动语态
在主动语态中，一些表示感官或使役的动词，如 hear/ watch/ see/ feel/ notice/ listen to/ look at/ let/ make/ have和 help等后面的宾语补足语是不带 to的动词不定式，但句子在变为被动语态后要加 to。如：
① He made the girl stay at home.→ The girl was made to stay at home.
② We often hear her sing in the room.→ She is often heard to sing in the room.
③ The boss made them work for 16 hours a day.→ They were made to work for 16 hours a day( by the boss).
4. 主动形式表被动意义
①动词 need， want以及短语 be (well) worth等后面常接动名词，以主动形式表示被动意义。如：
The room needs cleaning.这房子需要打扫。 The piece of music is worth listening to.这首曲子值得听。
②某些表示主语质地、自身特征的动词，如 write/ wash/ sell/ clean/ cook等，常和副词 well或 easily连用，用主动形式表示被动意义。如：
The cloth washes easily.这种布容易洗。 The pen writes well.这支笔很好用。
