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
A 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.
