被动语态复习

　　语态(voice)，作为一个语法范畴，是表示主语和动词之间的主动或被动关系的动词行式。英语动词有两种语态：主动语态(active voice)和被动语态(passive voice)。当主语为动作执行者即施动者时，动词用主动态；如果主语是动作的承受者即受动者时，动词便用被动态。例如：
　　(1) john helped peter.
　　(2) peter was helped by john.
　　句(1) helped是主动态；句(2)was helped是被动态,可见主动态是无标记的，而被动态是有标记的。
　　构成
　　被动语态由助动词be的时态之一和及物动词的过去分词构成。被动语态可用于各种时态，其时态变化通过助动词be的不同形式来体现。如：一般现在时的被动态构成形式为助动词am/is/are + 过去分词；而一般过去时的被动态构成形式为was/were + 过去分词。本册要掌握的被动语态形式有：
　　一般现在时：am/is/are + 过去分词
　　e.g. football is played all over the world.
　　i’m often asked to do this work.
　　我常常被派做这项工作。
　　一般过去时：was/were +过去分词
　　e.g. the terracotta warriors were found in 1974 near xi’an.
　　they were discovered by workers in a field outside the city.
　　when was the building completed?
　　这座大楼什么时候建成的？
　　一般将来时：will (shall) + be +过去分词
　　be going to + be + 过去分词
　　e.g. the result of the exam will be known soon.
　　they are going to be given a difficult test.
　　一般过去将来时：should(would) be+过去分词
　　e.g. the teacher said the results would be published soon.
　　he told me that the film would be shown the next week.
　　现在进行时：am/is/are + being +过去分词
　　e.g. the new airport is being built by a foreign company.
　　一家外国公司正在承建这座新机场。
　　the song is being sung by the girls now.
　　过去进行时：was/were being+过去分词
　　e.g. the song was being sung by the girls when i got there.
　　the student was being criticized when i went into the
　　teacher’s office.
　　将来完成时：will have been+过去分词
　　e.g. by the end of next term XX english words will
　　have been learned.
　　the building will have been built by next year.
　　现在完成时：has/have + bee n +过去分词
　　e.g. all the tickets have been sold .
　　the book has been translated into many languages.
　　这本书已被译成多种语言。
　　过去完成时：had been+过去分词
　　e.g. forty schools had been visited by last year.
　　all the tickets had been sold out when i got to the cinema.
　　过去将来完成时：would have been+过去分词
　　e.g. he said many words would have been learned by XX.
　　they promised that ten books would have been published
　　by the next month.
　　情态动词：情态动词 + be + 过去分词
　　e.g. this road must be mended.
　　the machine parts may be needed in our work.
　　工作中可能需要这些机器零部件。
　　动词不定式：to be + 过去分词
　　e.g. i’m glad to be asked questions.
　　it is impossible for lost time to be made up.
　　失去的时间不可弥补。
　　主要用法
　　被动态常用于下列几种场合：
　　1．当不知道或不必提出动作的执行者时（这时都不带由by引起的短语）；
　　printing was introduced into europe from china.
　　印刷术是从中国引入欧洲的。
　　the airplane was made in u.s.
　　such books are written for children. 这种书是为儿童写的。
　　2. 动作的承受者是谈话的中心（这时可带有由by引起的短语）；
　　the song was composed by a student.
　　这首歌曲是一个学生谱写的。
　　thousands of rivers are polluted in the country.
　　3. 出于礼貌措词等原因而不愿说出动作执行者是谁。
　　you are requested to get here in time.
　　请您准时来这儿。
　　带行为主体的被动态
　　行为主体就是动作的执行者，即执行动词所表达的动作的人或物。在被动句中，往往不提及行为主体；但当强调动作的执行者时，可用介词by引出行为( by +主体行为主体),置于被动态句的末尾，说明是什么人或物应对有关事件负责。
　　e.g. the village was destroyed by a bomb.
　　这个村庄毁于炸弹。
　　the painting is very valuable. it was painted by van gogh.
　　这幅画很值钱，它是梵•高画的。
　　其它用法补充
　　1.＂it + 被动语态+ that 从句＂。表示谨慎或不太肯定的语气。常用于该结构的动词有：say, think, believe, agree, expect, consider, feel, know, decide, report, suggest, prove 等。
　　e.g. it is said that prices will rise again this month.
　　据说本月物价还将上涨。
　　it is thought that about a million dogs are born each year.
　　据认为每年约有一百条狗出生。
　　it is reported that all the passengers died in the crash.
　　据报导所有乘客在那次飞机坠毁中遇难。
　　it is agreed that we will have two weeks holiday this year.
　　2. 用于通告标题广告等的被动态往往省去助动词be。
　　e.g. no chinese spoken here.
　　shoes repaired.
　　famous painting stolen. 名画被盗。