三、被动语态的使用范围

    1. 不知道或不必指出动作的执行者
    The cup is broken. 杯子破了。
    The audience is asked to keep silence. 观众被要求保持安静。
    The meeting is scheduled for April 6th. 会议定于4月6日举行。
    Raincoats are sold in the shop. 这家商店出售雨衣。
    2. 强调动作的承受者
    A new subway will be built in the city. 城里将建一条新地铁。
    Mr.Li was elected chairman of the committee. 李先生被选为委员会的主席。
    The first prize was won by Henry. 一等奖被亨利得了。
    3. 出于策略、婉转、礼貌等不提出动作的执行者
    Any suggestion or criticism is heartily appreciated. 真诚欢迎任何意见或批评。
    About that project，much has been said but little has been done. 关于那项工程，说的多做的少。
    That plan was generally considered not practical. 这个计划被普遍认为不切实际。
    You are cordially invited to the ceremony. 热忱邀请阁下参加这次典礼。
    Customers are requested not to touch the exhibits. 顾客请勿触摸展品。
    4. 避免变更主语，以求行文通顺
    She gave a lecture on modern American poetry and was attentively listened to. 她作了一个关于美国现代诗歌的演讲，很受欢迎。
    The old professor wheeled himself to the platform and the students warmly applauded him. （不简洁）
    The old professor wheeled himself to the platform and was warmly applauded by the students. 老教授手摇轮椅来到讲台上，受到学生们的热烈欢迎。（简洁、连贯）
    5. it+be+过去分词+that-从句
    这是一种惯用结构，常用的动词有：say, report, expect, allege, prove, suppose等。例如：
    It is reported that gold has been found there. 据报道那里发现了黄金。
    It is said that the original painting has been destroyed. 据说原画已经毁掉了。
    It is expected that prices will go down. 预计物价将会下跌。
    It was alleged that the child was kidnapped. 据称那个孩子被绑架了。
    It is feared that the plane crashed somewhere off the coast. 恐怕那架飞机在海岸外某处坠毁了。
    It is believed that he is the manager of three different businesses. 据信他是三家不同公司的经理。
    6. be+过去分词+不定式
    He is considered to be an authority in the field. 他被认为是这个领域的权威。
    It's supposed to be most valuable. 据说它非常有价值。
    He was said to have disclosed the secret. 据说他泄露了秘密。
    They were reported to be sailing in the Pacific. 据报道他们正在太平洋上航行。
    She is thought to be a good singer. 她被认为是一个优秀歌手。
    He is rumored to have escaped into the mountains. 谣传他逃到山里去了。
    He is alleged to have bribed government officials. 据称他贿赂过政府官员。
    The good weather is expected to last another week. 好天气预计还要持续一周。
    One-eighth of our warm air is claimed to be lost through the windows. 房间暖气的八分之一据称是从窗户走漏的。
    This is the school where the kids are alleged to break windows all day long. 据说这就是孩子们整日砸窗户的学校。
    7. there+be+过去分词
    There is said to be a secret tunnel beneath the building. 据说这幢大楼下面有一条秘密通道。
    There are supposed to be wild animals in the hills. 这山里应有野生动物。
    There are known to be thousands of snakes on the island. 据了解，那座岛上有成千上万条蛇。
    【提示】
    ① 有些时候，被动语态会给人一种冷淡、疏远、公事公办的感觉，或者可信度并不那么强。比较：
    Aunt is taking care of the child. 姑妈在照看孩子。（主动，熟悉，亲切）
    The child is being taken care of. （被动，疏远，冷淡）
    Mother told me that. 母亲告诉了我那个。（主动，可信度强）
    I was told about that on the train. （被动，可信度小）
    ② 被动句中的by短语通常可以省去。但如果by短语是句子的重点所在，或者没有by短语则句义不完全时，则不可省。例如：
    The tool was made by my father. 这件工具是父亲制作的。（the tool为已知事物，my father为新的信息，是重点所在，不可省）
    The meeting was followed by a short interval. 会后是短暂的间歇。（by a short interval不可省，否则句义不清）
    ③ 在被动句中，by短语通常位于过去分词之后；但如果有间接宾语或同其他状语并列使用时，则by短语通常位于其后。例如：
    She was given a new pen by her father. 我父亲给了她一支新钢笔。
    Taking a walk is considered a good exercise by most people. 大多数人都认为散步是一项好运动。
    They are watched naturally very closely by the soldiers. 他们很自然被士兵严密监视着。
    JJ 下面一句把to her sister放在句尾，是对其进行强调，为尾重句：
    The cap was given by me to her sister. 这顶帽子是我送给我妹妹的。