不定式的被动式的概念：

如果不定式的逻辑主语是不定式所表示的动作的承受者，不定式要用被动式。如：The next thing to be done is to get our classroom pained.

不定式被动式的用法：

一、基本形式：
不定式被动式的基本形式为to be done；若表示动作先于另一动作之前，则用完成式，即to have been done。

二、用法归纳：
不定式被动式在句中可以用作：
1、主语：
如：It's a great honour to be invited to the banquet. 承蒙邀请赴宴，甚是荣幸。
        To be attacked by the enemy is not a bad thing, but a good tiring. 被敌人反对是好事，不是坏事。
        It's a pity to be kept in the house in fine weather. 好天气时被留在家里是很遗憾的。
2、表语：
如：All this is to be sold. 所有这些都是出售的。
        Water must be pure if it is to be drunk. 水如供饮用必须净化。
        The switchboard is to be manned at all times. 任何时候电话总机那儿都应有专人在岗负责。
3、宾语：
如：She doesn't want to be separated from him. 她不愿和他分开。
        He begged to be allowed to return to Brazil. 他恳求允许他返回巴西。
        I don't wish to be disturbed in my work. 在工作时我不愿意被人打扰。
        They demanded to be shown the authentic documents. 他们要求出示真实可靠的文件。
4、定语：
如：I made notes of the things to be mended. 我记下了需要修补的东西。
       The Blacks are the first to be fired and the last to be hired. 黑人是最先被解雇，最后被雇用。
5、状语：
如：He asked to be kept in formed about developments. 他要求随时向他报告发展情况。
        As she waited to be served, she became very impatient. 她在等候侍者送饭时，很不耐烦。
        She got there only to be told that they had gone on holiday. 她到达那里，被告知他们度假去了。
6、宾语补足语：
如：He did not like his intention to be laughed at. 他不喜欢自己的意图受到嘲笑。
        He ordered the goods to be sent by air. 他命令把货物空运
7、主语补足语：
如：The court was ordered to be cleared. 有命令要关闭法庭。
        The books are not allowed to be taken out of the room. 不许将书携出室外。
8、用在“for+名(代)词+不定式”结构中。
如：It's an honour for me to be asked to speak here. 我很荣幸被邀在这里讲话。
        It is essential for him to be prepared for this. 有必要让他对此有所准备。
        It's impossible for the job to be finished in time. 这项任务要按时完成是不可能的。
        The note was a simple request for a porter to be sent to room201. 这个字条就是请指派一个搬运工到201室去。
        Can you arrange for the gold to be delivered on Monday? 你能不能安排一下周一把金子送到?

动词不定式的被动式之注意点：

 一、注意形式与功用：
不定式的被动式为“to be＋过去分词”，表示其逻辑主语是动作的承受者，具有被动含义。在句中可用作主语、表语、宾语、定语、状语、补语等。
如：It was impossible for lost time to be made up. 要弥补已失去的时光是不可能的。
        I hope to be invited to the party. 我希望有人请我去参加晚会。
        Have you got ready for the meeting to be held? 你为即将举行的会议准备好了吗？ 
        In order to be chosen, he sent each of them a present.为 了被选中，他给他们每人都送了礼物。
        The problem seems to be solved soon. 问题好像快要解决了。

二、与不定式的主动式的比较：
1、表示义务的概念，句子的主语是要做的动作或接受动作的人或物时，要用不定式的被动式。
如：These sheets are to be washed. 这些床单要洗一洗。
        The cleaning is to be finished by mid day. 要在中午前打扫完毕。
2、不定式作定语与被修饰词是主谓、动宾、同位等逻辑关系时，多用其主动式。
如：Where is the boy to speak at tomorrow's meeting?(=who will speak at tomorrow's meeting主谓关系) 明天要在会上发言的那个男孩在哪里？ 
        I have got a letter to write.(=that I will write动宾关系，尤其谓语动词为have, give, bring等时) 我有封信要写。
       Give me a pen to write with.(=that I can write with不及物动词加上相应的介词)给我一枝笔写。
注意：如果动作的执行者在主语或宾语中没有出现，应用不定式的被动式。
如：I'm going to the post office. Do you have any letters to be posted? 我要去邮局。你有信要寄吗？（动作执行者不是you）
3、在there be结构中，用不定式的主动式和被动式意义一般差别不大，但有些还是有差别的。
如：There's a lot to be said (或to say) about this book. 关于这本书大有可说。
        There is nothing to see. 没有什么可看的了。
        There is nothing to be seen. 看不见有什么。(即“什么也没看见”)
4、修饰作表语或宾补的形容词的不定式，常用主动式表示被动含义。
如：I don't think English hard to learn. 我认为英语不太难学。

三、双重被动结构有些被动结构后接不定式作宾语、宾语补足语等时，仍然含有被动含义，就得用双重被动结构：
如：The work is thought to be finished soon. 大家认为工作很快就完成了。

四、动作发生的时间不定式多表示未来动作或情况，其被动式也不例外，上述各例皆有体现，尤其是改为定语从句时多为将来时的被动语态。另外我们还要注意以下两点：
1、表示被动关系时，当不定式的动作先于谓语时，可用不定式的被动式的完成时：to have been done；
与谓语同时进行时，要用不定式的被动式的进行时：to be being done。
如：The dead woman is said to have been badly treated. 据说死去的妇女受虐待。
        Rain forests are reported to be being cut down rapidly. 据报道雨林正被迅速地砍伐。
2、不定式的主动式作含序数词的被修饰词语的定语时，可表示已完成的动作。
如：He was the first man to taste the tomato. 他是第一位品尝西红柿的人。
        They were the last to leave the countryside.他们是最后一批离开农村的。