被动语态怎么讲

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.二、 怎样把主动语态改成被动语态?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.3.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.6.You must lock the door when you leave.→the door must be locked when you leave.