初中英语被动语态的讲解定义：英语中有两重语态：主动语态和被动语态。
主动语态中的主语是动作的执行者，被动语态中的主语是动作的承受者，即主动语态中的宾语。
所以只有及物动词才有被动语态。
规则：被动语态由“助动词be+及物动词的过去分词”构成。
第一，助动词be 要随着人称和数的变化而变化，第二，助动词be 要随着时态的变化而变化。
一、被动语态的构成形式1. 被动语态的基本时态变化以do 为例，各种时态的被动语态形式为：1) am/is/are +done (过去分词) 一般现在时例Visitors are requested not to touch the exhibits.2）was/were done 一般过去时例I was given ten minutes to decide whether I should reject the offer.3）shall/will be done 一般将来时例Hundreds of jobs will be lost if the factory closes.4）am/is /are being done 现在进行时例A new cinema is being built here．5）was/were being done 过去进行时例A meeting was being held when I was there.6）should/would be done 过去将来时例The news would be sent to the soldier's mother as soon as it arrived.7）has /have been done 现在完成时例All the preparations for the task have been completed, and we're ready to start.8）had been done 过去完成时例By the end of last year, another new gymnasium had been completed in Beijing.9）shall/will have been done 将来完成时（少用）例The project will have been completed before July.2．被动语态句型变化肯定句主语+be+过去分词，否定句主语+be not+过去分词，一般疑问句Be+主语+过去分词，特殊疑问句疑问词+be+主语+过去分词。
3.被动语态的特殊形式1) 带情态动词的被动结构。
其形式为：情态动词＋be＋过去分词。
例The baby should be taken good care of by the baby-sitter.2) 双宾语结构。
主动结构中的一个宾语变为主语，另一宾语仍然保留在谓语后面。
通常变为主语的是间接宾语。
例His mother gave him a present for his birthday. He was given a present by his mother for his birthday.3) 当“动词+宾语+宾语补足语”结构变为被动语态时，将宾语变为被动结构中的主语，宾补不变。
例Someone caught the boy smoking a cigarette. The boy was caught smoking a cigarette （by some one）.4）在使役动词have, make, get 以及感官动词see, watch, notice, hear, feel, observe 等后面不定式作宾语补语时，在主动结构中不定式to 要省略，但变为被动结构时，to 要还原。
例Someone saw a stranger walk into the building. A stranger was seen to walk into the building.5) 有些相当于及物动词的动词词组，如“动词＋介词”，“动词＋副词”等，用于被动结构，要看作一个整体，不能分开。
其中的介词或副词也不能省略。
例The meeting is to be put off till Friday.6）非谓语动词的被动语态。
v.+ing 形式和to do 不定式的被动语态。
例I don't like being laughed at in the public.二、被动语态的基本用法1. 讲话者不知道动作的执行者或不必说出动作的执行者(这时可省by 短语)。
例My bike was stolen last night.2. 为了强调动作的执行者例I was given ten minutes to decide whether I should accept the offer.3. 为了美化句子结构。
例The well-known person got on the bus and was immediately recognized by people. （避免主语多次重复）三、It is said that+从句句型表示据说，相信等意义的动词，如believe, consider, expect, report, say, suppose, think 等可以用于句型“It ＋be＋过去分词＋that 从句”或“主语＋be＋过去分词＋to do sth.”。
如：It is said that… 据说,It is reported that…据报道，It is believed that…大家相信，It is hoped that…大家希望，It is well known that…众所周知，It is thought that… 大家认为，It is suggested that…据建议。
例It is said that the boy has passed the national exam. The boy is said to have passed the national exam.四．非谓语动词的被动语态非谓语动词：非谓语动词包括不定式、动名词和分词三种形式，在句中充当除谓语以外的其他各种成分，即主语、表语、宾语、补语、定语和状语。
例：Not being tall is not aserious disadvantage in life. （作主语）I like getting up early. （作宾语）I heard someone singing his song.（作补语）There is a car stopping outside. （作定语）He came to see me. （作状语）1. 动名词形式的的被动语态主动句：V+ing 被动句：being+分词He is happy to hear someone singing his song. He is happy to hear his song being singed.2. 不定式形式的被动语态主动句：to do 被动句：to be done I hate to dress up like a fool. I hate to be dressed up like a fool.五、非谓语动词的主动形式表被动意义在某些句型中可用动名词和不定式的主动形式表被动意义。
1．在need，want，require, bear 等词的后面，动名词用主动形式表示被动意义，其含义相当于动词不定式的被动形式。
The house needs repairing（to be repaired）．这房子需要修理。
2．形容词worth 后面跟动名词的主动形式表示被动含义，但不能跟动词不定式；而worthy 后面跟动词不定式的被动形式。
The picture-book is well worth reading．（＝The picture-book is very worthy to be read．）3. 在某些“形容词＋不定式”做表语或宾语补足语的结构中，句子的主语或宾语又是动词不定式的逻辑宾语时，这时常用不定式的主动形式表达被动意义。
这些形容词有nice，easy，fit，hard，difficult，important，impossible，pleasant，interesting 等。
This problem is difficult to work out .（可看作to work out 省略了for me）. 44．在too.... to...7结构中，不定式前面可加逻辑主语，所以应用主动形式表示被动意义。
This book is too expensive (for me) to buy.5. 在there be...句型中，当动词不定式修饰名词作定语时，不定式用主动式作定语，重点在人，用被动形式作定语，重点在物。
There is no time to lose（to be lost）．（用to lose 可看成for us to lose；用to be lost，谁lost time 不明确。
）6. 在be to do 结构中的一些不定式通常应用主动表主动, 被动表被动。
然而,由于古英语的影响,下列动词rent, blame, let 等仍用不定式的主动形式表示被动意义。
Who is to blame for starting the fire?7. 介词in, on, under ... + 名词构成的介词短语表示被动意义。
The house facing the tower is in the possession of Mr Bob. 面对着塔的屋子是Bob 的。
六、不及物动词的被动结构不及物动词没有被动语态，因为不及物动词没有宾语1. 一些表示发生、状态的不及物动词主动形式表示被动happen, belong to, suit, fit(适合), have, let, join, fall, last （延长）,cost, break out （爆发）appear, burst out(迸发)，hold(容纳)，lack（缺乏），agree with This room can hold 500 people. Taiwan belongs to China. The T-shirt fits me very well, and it only cost 20 yuan. SARS broke out in China that year. Great changes have taken place in the last ten years in China .2. 可利用介词in, on, under ... + 名词构成的介词短语表示被动的形式，将不及物动词转化为对应的名词。