一、主动语态与被动语态

决定动词用主动语态还是被动语态主要看动词和主语的关系。如果主语是动作的执行者，它们就是主动关系，动词就要用主动语态。如果它是动作的承受者，它们就是被动关系，动词就需要用被动语态。

1.谓语动词和主语的关系

（1）执行者 or 承受者？

主动语态（主语为动作的执行者） 被动语态（主语为动作的承受者）

Lu Xun wrote the book.The book was written by Lu Xun.

They took her to hospital.She was taken to hospital.

I painted the walls yellow.The walls were painted yellow.

（2）只有承受者：

被动语态很重要，因为在不少情况下，执行者不明确，不能或无须提及，句子中只有动作的承受者，它就成为句子的主语。

He was born in Wales.

Two people were injured in the accident.

（3）形式主动，意义被动：

Where is the new film showing?

I am to blame.

2.能用于被动语态的动词

（1）及物动词用于被动语态：

及物动词有宾语，把宾语用作主语时，它和动词才有被动关系。

Over a hundred people were invited to the banquet.

President Kennedy was assassinated.

（2）不及物短语动词用于被动语态：

不及物动词没有宾语，因此很少用于被动语态。但有些短语动词，即使是由不及物动词构成，也可以有宾语，因此可以用于被动语态：

A pedestrian was knocked over by a car.

They feel they are discriminated against.

（3）情态动词和某些动词结构用于被动语态：

All the invitations must be sent out today.

A press conference is about to be held.

（4）非谓语动词的被动形式：

非谓语动词（即动词的非限定形式）虽不能改为被动语态（因为被动语态是谓语的一种形式），却可以有被动形式（不定式、动名词等都有被动形式）：

She asked to be given some work to do. （不定式）

He hated being flattered. （动名词）

Being protected by a wall, he felt quite safe. （分词）

3.被动结构的句子

一个主动结构的句子，若要变成被动结构，首先是把句子的宾语变成主语，其次把谓语改为被动语态，最后把原来的主语放到句末，前面加介词 by：

（1）句子的被动结构：

（2）不用 by 引起的短语而用其他短语：

（3）没有 by 引起的状语，而有其他状语：

（4）其他结构：

① 主语+谓语（跟不定式）

They were forced to work twelve hours a day.

The box was found to be empty.

② 主语+谓语（跟一名词作补语）

He was elected chairman.

She was called Cinderella.

③ 主语+谓语（加形容词等作补语）

The door was painted black.

The room should be kept clean.

④ 主语+谓语+保留宾语+其他部分

He was given something to read.

They are taught many subjects at school.

这类句子的主动结构有两个宾语即直接宾语和间接宾语，当句子变为被动结构时，间接宾语多变成主语，直接宾语保留下来，称为保留宾语（retained object）。

⑤ It+谓语+主语从句

It is said that his income is ￡200 an hour.

It is rumored that he is going to resign. O/jsmofy6d16V57d/DE/EVl7HJ/J3t9gdYx7KHAq/IUG5VI1ze81o5PeOXjZKYer