双重被动句
句型［主语+被动式谓语+被动不定式+其他］
1.The date is expected to be announced soon.
2.The gate was ordered to be closed at nine oclock.
3.The books are not allowed to be taken out of the room.
4.These arms are supposed to have been used by partisans during the anti-Japanese war.
5.The task is reported to have been completed yesterday.
6.The instruments are supposed to be used only by skilled workers.
[注] H. W. Fowler 说过，双重被动式，从文体学观点来看是应该尽量避免，因为从表面看来容易为类似的假象所混淆。如：(错) The house was begun to be built. 不是房子开始而是房子的建造开始。下列动词不适宜于本句型：attempt, decide, promise, seek, begin, hope, intend, propose, purpose, threaten等。
不可说：The work was attempted to be done quickly. 应当说：An attempt was made to do the work quickly.
不可说：He has been decided to be helped. 应当说：It has been decided to help him. It has been decided that he should be helped.
[附注]主动语态与被动语态互相转换时应注意的几点事项。
1）基本转换公式：省略。
2）转换时一般不得变更动词的时态。另下列各时式不能用于被动句中。
1. 将来进行时 2. 现在完成进行时 3. 将来完成进行时 4. 过去完成进行时
3）被动句中by后接 us, you, them, one时，by短语可以省略。
4）祈使句中使用被动式谓语很少见，以下各句可说是例外：Please be seated. Be trusted rather than feared.
一般情况使用let帮助构成祈使句的被动语态。
Do one thing at a time. Let one thing be done at a time. Give him something to eat. Let something to eat be given (to) him. /Let him be given something to eat.
5）在下列情况下，主动句不能转换成被动句。1. 由于宾语的性质不用被动句：
A. 当宾语是缺乏实义的代词it时，不能变，如：walk it, go it, fight it out
B. 当宾语为反身代词时，不能变，如: (错) Himself was absented by him.
C. 宾语前若有主语的物主代词时，不能变，如: (错) His finger is cut by him.
D. 当宾语是each other或one another时不能变，如: (错) Each other is helped by us.
E. 当宾语是不定式时，很少转用于被动句。不宜说：To go is wanted by me或It is wanted by me to go.
2. 由于某些动词的性质不用被动句, 这类动词有：become, befit, fail, last, resemble, suit, suffice, wish, disappear, lack want, like, hate, possess, own, contain, have, happen to, belong to, break out, take place, set sail, shake hands with, take part in等。
3. 当某些动宾关系十分紧密不可分割时不能变被动句。这种组合中的宾语大多表示工具、方式或结果，如：She leaned her elbows on the table. He kept silence. He took (made) a flight. The boy did not lose heart. Nydia bowed her gratitude.
4. 容易发生歧义的句子最好不用被动句，如：The tall doctor shook his head.
6) 有些被动句不能变成主动句，如：He was killed in war. It is said that he is ill.