第2个回答 推荐于2017-09-13
中文里有把字句和被字句的概念，把字句可以表示主动，强调动作的执行者，被字句表示被动，强调动作的承受者。英语里也有主动语态和被动语态的概念，与中文的“把字句”和“被字句”的概念相似。一般来说，只有及物动词才有被动语态。
被动语态一般由助动词be加上及物动词的过去分词构成。助动词be是表示时态的，过去分词表示被动的动作。
主动语态变成被动语态的时候，及物动词的宾语先变成被动句的主语，动词变成被动语态，原来的主语变成介系词by引出来：
The pictures were taken by a professional photographer.
I was given a bike by my aunt. （动词有双宾语时，直接宾语和间接宾语均可用作被动句的主语）
The boy was found dead in the woods. （动词有复合宾语时，宾语原来有补语，变成被动语态时，宾语补语留在谓语之后，一些要求没有to的动词不定式作宾语补语的动词，变成被动语态后，这时的动词不定式加上to）
Heat is given off by the chemical change.
The matter was often talked about.
Much attention was paid to the safety of the passengers.
Iron is made use of in various ways.
The loss has been made up for.
It hasn't been found out when the plane takes off.
疑问句的被动语态，一般疑问句是把助动词be提到主语之前，如：
Was the pizza baked by your father?
特殊疑问句，开头是特殊疑问词，接着是助动词be，然后才是主语，如：
Who was suspected by the police?
By whom was the CD produced?
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