学习英语，了解英语语态的重要性不亚于时态。
说话，写作时，我们必须要搞清楚事物之间的关系，动作是主动发出的，还是被动实现的。
语态（Voices）用来表示主语与谓语之间的关系，它是动词一种形式。英语中有两种语态：主动语态（Active Voice）和被动语态（Passive Voice）。主动语态表示主语是动作的执行者，而被动语态表示主语是动作的承受者。
主动语态转换为被动语态的步骤：先将主动句中的宾语变为被动句中的主语；再将主动句中的谓语变成被动形式；最后将主动句中的主语变为由 by 引起的短语并后置。
The government supported the research.
The research was supported by the government.
2. 主动句为：主语 + 谓语 + 间接宾语 + 直接宾语
变成被动句时，有两种情况：把间接宾语变为被动句的主语，直接宾语位置不变；把直接宾语变为被动句的主语，间接宾语前面加上介词 to 或 for。例如：
My parents bought me a new computer.
→ I was bought a new computer.
→ A new computer was bought for me.
3. 主动句为：主语 + 谓语 + 宾语 + 宾语补足语
变成被动句时，将宾语变为被动句的主语，宾语补足语位置不变。例如：
People call this team a cheerleading squad.
（主动句，宾语补足语为a cheerleading squad）
→ The team is called a cheerleading squad.
这个队被叫做拉拉队。（被动句，主动句中的宾语补足语a cheerleading squad变成了主语补足语）
变成被动句时，有两种情况：常用 it 作形式主语，将宾语从句变为主语从句放在句尾；
将主动句中从句的主语变为被动句的主语，从句谓语及其他成分改为不定式短语。例如：
We know that he is the best doctor in the town.
→ It is known to us that he is the best doctor in the town.
我们知道他是城里最好的医生。(it作被动句的形式主语)
→ He is known to be the best doctor in the town.
他被认为是城里最好的牙医。 (主动句中从句的主语变成被动句的主语，从句的谓语变成不定式)
1. 一般现在时：am / is / are + 过去分词
Many tall buildings are built in months.
2. 一般过去时：was / were + 过去分词
The soil was washed away by the water.
3. 一般将来时：shall / will be + 过去分词
As cities grow, more water will be used.
4. 现在进行时：am / is / are being + 过去分词
We all feel very excited when the national flag is being raised.
5. 过去进行时：was / were being + 过去分词
We couldn’t use the reading-room. It was being repaired.
6. 现在完成时：have / has been + 过去分词
Soil has been washed into the river from the riverbank.
含情态动词的被动语态由“情态动词 + be + 过去分词”构成。例如：
Nothing can be learned without hard work.
有不少短语动词相当于及物动词，可以有被动语态。含有短语动词的主动句变为被动句时，其中的副词或介词不可漏掉。例如：
I was brought up in a small village.
含 be going to，used to，have to，had better 等结构的主动句变为被动句时，只需将其后的动词变为被动形式即可。例如：
The sports meeting is going to be held soon.
不知道动作的执行者，没有必要指出动作的执行者或强调动作的承受者时，常使用被动语态。例如：
In the future all shopping will be done online.
一般说来，及物动词都有被动语态，但少数及物动词如 have，leave，become，cost，enter，reach，suit，benefit，lack 等以及短语动词 take place，lose heart，break out，belong to，consist of 等，一般不能用于被动语态。例如：
When we reached a valley, it became much warmer.
某些系动词 taste，feel，look，smell，sound，prove 等与形容词连用时。例如：
发表评论