不用被动语态的情况
1） 不及物动词或动词短语无被动语态：
appear,die disappear,end (vi. 结束),fail,happen,last,lie,remain,sit,spread,stand
break out,come true,fall asleep,keep silence,lose heart,take place.
After the fire,very little remained of my house.
比较：rise,fall,happen是不及物动词；raise,seat是及物动词。
(错) The price has been risen.
(对) The price has risen.
(错) The accident was happened last week.
(对) The accident happened last week.
要想正确地使用被动语态，就须注意哪些动词是及物的，哪些是不及物的。特别是一词多义的动词往往有两种用法。解决这一问题唯有在学习过程中多留意积累，勤加练习。
2） 不能用于被动语态的及物动词或动词短语：
fit,have,hold,marry,own,wish,cost,notice,watch agree with,arrive at / in,shake hands with,succeed in,suffer from,happen to,take part in,walk into,belong to
This key just fits the lock.
Your story agrees with what had already been heard.
3） 系动词无被动语态：
appear,be become,fall,feel,get,grow,keep,look,remain,seem,smell,sound,stay,taste,turn
It sounds good.
4） 带同源宾语的及物动词，反身代词，相互代词，不能用于被动语态：
die,death,dream,live,life
She dreamed a bad dream last night.
5） 当宾语是不定式时，很少用于被动语态。
(对) She likes to swim.
(错) To swim is liked by her.
主动形式表示被动意义
1）wash,clean,cook,iron,look,cut,sell,read,wear,feel,draw,write,sell,drive…
The book sells well. 这本书销路好。
This knife cuts easily. 这刀子很好用。
2）blame,let(出租),remain,keep,rent,build
I was to blame for the accident.
Much work remains.
3） 在need,require,want,worth (形容词),deserve后的动名词必须用主动形式。
The door needs repairing.= The door needs to be repaired.
This room needs cleaning. 这房间应该打扫一下。
This book is worth reading. 这本书值得一读。
4） 特殊结构：make sb. heard / understood (使别人能听见/理解自己)，have sth. done (要某人做某事)。
被动形式表示主动意义
be determined,be pleased,be graduated (from),be finished,be prepared (for),be occupied (in),get marries
He is graduated from a famous university.
他毕业于一所有名的大学。
注意：表示同某人结婚，用marry sb. 或get married to sb. 都可。
He married a rich girl.
He got married to a rich girl.
need/want/require/worth
注意：当 need,want,require,worth(形容词)后面接doing也可以表示被动。
Your hair wants cutting. 你的头发该理了。
The floor requires washing. 地板需要冲洗。
The book is worth reading. 这本书值得一读。
被动语态更多介绍
一、 被动语态的用法：
⒈一般现在时的被动语态构成：is / am / are + 及物动词的过去分词
Our classroom is cleaned everyday.
I am asked to study hard.
Knives are used for cutting things.
⒉一般过去时的被动语态构成：was / were + 及物动词的过去分词
A new shop was built last year.
Dinosaur eggs were laid long long ago.
⒊现在完成时的被动语态构成：has / have + been + 及物动词的过去分词
This book has been translated into many languages.
Many man-made satellites have been sent up into space by many countries.
⒋一般将来时的被动语态构成：will+ be + 及物动词的过去分词
A new hospital will be built in our city.
Many more trees will be planted next year.
⒌含有情态动词的被动语态构成：情态动词+ be + 及物动词的过去分词
Young trees must be watered often.
Your mistakes should be corrected right now.
The door may be locked inside.
Your homework can be handed in tomorrow.
⒍现在进行时的被动语态构成：am / is / are + being + 及物动词的过去分词
Uncle Wang is mending my bike now.→
My bike is being repaired by Tom now.
They are planting trees over there. →
Trees are being planted over there by them.
⒎不定式的被动语态：to + be + 及物动词的过去分词
There are two books to be read. →
There are twenty more trees to be planted.
二、 怎样把主动语态改成被动语态?
把主动语态改为被动语态非常简单，可以遵循以下几个步骤：
⒈先找出谓语动词；
⒉再找出谓语动词后的宾语；
⒊把宾语用作被动语态中的主语；
⒋注意人称、时态和数的变化。
例：1. Bruce writes a letter every week. →A letter is written by Bruce every week.
⒉Li Lei mended the broken bike this morning.→The broken bike was mended by Li Lei this morning.
⒊He has written two novels so far.→Two novels have been written by him so far.
⒋They will plant ten trees tomorrow.→Ten trees will be planted by them tomorrow.
⒌Lucy is writing a letter now.→A letter is being written by Lucy now.
⒍You must lock the door when you leave.→the door must be locked when you leave.
三、 使用被动语态应注意的几个问题：
⒈不及物动词无被动语态。
What will happen in 100 years
The dinosaurs disappeared about 65 million years ago.
⒉有些动词用主动形式表示被动意义。
This pen writes well.
This new book sells well.
⒊感官动词或使役动词使用省略to的动词不定式，主动语态中不带to ，但变为被动语态时，须加上to。
例：make somebody do something→somebody+ be +made to do something
see somebody do something→somebody +be +seen to do something
A girl saw my wallet drop when she passed by.→My wallet was seen to drop by a girl when she passed by.
The boss made the little boy do heavy work.→The little boy was made to do heavy work by the boss.
⒋如果是接双宾语的动词改为被动语态时，直接宾语(物)作主语，那么动词后要用介词，这个介词是由与其搭配的动词决定。
He gave me a book.→A book was given to me by him.
He showed me a ticket.→A ticket was shown to me by him.
My father bought me a new bike. →A new bike was bought for me by my father.
⒌一些动词短语用于被动语态时，动词短语应当看作一个整体，而不能丢掉其中的介词或副词。
We can’t laugh at him. →He can’t be laughed at by us.
He listens to the radio every day. →The radio is listened to by him every day.
动词的分类
动词分为五种：及物动词，不及物动词，连系动词，助动词和情态动词
⒈及物动词：是指后面需要使用宾语是其意义完整的动词.
如：那条狗使这个孩子高兴起来。That dog makes the boy happy.
⒉不及物动词：是指后面不需要宾语而意义完整的动词
如：我住在北京. I live in Beijing.
⒊连系动词：一个表示谓语关系的动词，后面必须接表语（通常为名词或形容词）一起使用。
最主要的联系动词是be (am is are). 其他常用的连系动词还有：seem 似乎 look 看起来 appear 好象 become 变成 keep 保持 get （成为）
如：他是一位好教师。He is a good teacher.
这花很好闻。The flower smells good.
⒋助动词：是指用来帮助主要动词完成语法功能的动词。这类动词本身没有意义，不能单独作谓语。他们可以在句中与实义动词一起帮助构成疑问句，否定句，进行时态，完成时态和将来时态。
助动词有：
Be （构成进行时） 如：我正在读书。I am reading a book.
Do （构成疑问句，否定句） 如：你喜欢苹果吗？不，我不喜欢。Do you like apple? No,I don’t.
Have （构成完成时态） 如：我明天来看你。I will come to se you tomorrow.
⒌情态动词：是指表示说话人的语气或者情态的动词。情态动词没有人称和数的变化，词义不完全 在句中不能单独作谓语，必须与后面的动词原形合用。
我们常用的情态动词有：
Can （能，会） 如：I can swim. 我会游泳。
May （可以） 如：You may go now. 你现在可以走了。
Must （必须） 如：You must do your homework. 你必须写作业。
Need （需要） 如：He needs our help. 他需要我们的帮助。
二、动词的基本形式
绝大多数动词都有五种基本形式：动词原形、一般现 在是第三人称单数、过去时、过去分词和现 在分词。
A、 第三人称单数形式的构成
一般现在时主语是第三人称单数，谓语动词后要加s或es，其变化规则与名词变复数的方法大体相同：
⒈一般情况下只在动词后加s，如work-works,write-writes。
⒉以s,x,sh,ch结尾的动词，后加es，如guess-guesses,mix-mix,finish-finishes,catch-catches。
⒊以辅音字母加y结尾的动词，改y为i，如study-studies。
注：不规则变化的有have-has，be-are，go-goes，do-does等。
B、 现在分词的构成
⒈一般情况下在动词后加ing，如study-studying，work-working。
⒉以不发音的字母e结尾的动词，去“e”再加“ing”，如write-writing，move-moving。
⒊以一个元音字母和一个辅音结尾的重读音节结尾的动词，要双写最后字母再加“ing”，如get-getting，begin-beginning。
⒋以ie结尾的动词，一般将ie改为y，再加ing，如lie-lying，die-dying，tie-tying。
注：以I结尾的动词，尾音节重读时，双写I，如control-controlling；尾音节不重读时，双不双写都可以，如 travel-traveling（美）/travelling（英）。
C、过去式的构成
⒈一般情况直接加ed，如ask-asked，work-worked。
⒉以不发音的e结尾，只加d，如love-loved，dance-danced。
⒊以辅音字母加y结尾，把y改i，如try-tried，study-studied。
⒋以一个元音字母和一个辅音结尾的重读音节结尾的动词，先双末尾一个字母，再加ed，如stop-stopped，permit-permitted
