1.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.
    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.
    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.
    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.
    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.
    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.
    不定式的
    

被动语态：to + be + 及物动词的过去分词
    二、 怎样把主动语态改成被动语态?
    

There are two books to be read. → 　　There are twenty more trees to be planted.
    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：
    先找出谓语动词;
    再找出谓语动词后的宾语;
    把宾语用作被动语态中的主语;
    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. 　　2. Li Lei mended the broken bike this morning.→The broken bike was mended by Li Lei this morning.
    He has written two novels so far.→Two novels have been written by him so far. 　　4. They will plant ten trees tomorrow.→Ten trees will be planted by them tomorrow. 　　5. Lucy is writing a letter now.→A letter is being written by Lucy now.
    三、 使用被动语态应注意的几个问题：
    

You must lock the door when you leave.→the door must be locked when you leave. 　　
    不及物动词无被动语态。
    What will happen in 100 years.
    The dinosaurs disappeared about 65 million years ago.
    有些动词用主动形式表示被动意义。
     (责任编辑：admin)