一、 被动语态的用法： 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. 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.