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.8.过去将来时的被动语态：would + be + 及物动词的过去分词 He said he would finish the work soon.He said the work would be finished soon by him.