被动语态由“助动词be+及物动词的
过去分词”构成。被动语态的时态变化只改变be的形式，过去分词部分不变。疑问式和否定式的变化也如此。
一般用法
1.一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 by my mother.
Knives are used for cutting things.
2.一般过去时的被动语态构成：was / were + 及物动词的过去分词
The new shop was built last year.
Dinosaur eggs were laid long long ago.
3.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.
4.一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.
5.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.
6.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.
7.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.
特殊用法
1.
不及物动词无被动语态。 如：happen, break down, come out......
What will happen in 100 years.
The dinosaurs disappeared about 65 million years ago.
2.有些动词用主动形式表示被动意义。 如： write, sell, ride.....
This pen writes well.
This new book sells well.
3.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.
4.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.
5.一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.
The nurse is taking care of the sick man. →The sick man is being taken care of by the nurse.
构成
be+done.