选修七Unit 2语法：to不定式的被动式一、概念：当to不定式与其逻辑主语构成被动关系时，要用to不定式的被动形式。
to 不定式的被动式主要有两种：一般被动式：to be done (表示其动作与谓语动词同时发生或发生在谓语动词之后); 完成被动式：to have been done (表示其动作发生在与谓语动之后或早已发生)。
二、用法1、作主语：It’s possible for our dream to be realized比较: It’s impossible for us to ___________ (realize) our dream. It’s an honor to be invited to speak here.比较: It’s an honor to _____________ (speak) here.Sometimes to be understood is not easy.比较: Sometimes to___________(understand) others is not easy 2.、作宾语He hated to be laughed at.比较: He hated to ___________(laugh) at others.I wanted to be sent there.比较: I wanted to ___________(send) him there.I feel it an honor to be asked to speak here.比较: I feel it an honor to __________(speak) here.3、作宾补I expected the plan to be carried out. 比较:I expected you to __________(carry) out the plan.I want my friend to be praised.比较: I want people to __________(praise) my friend.4、作主补The plan was expected to be carried out.比较: He was expected to__________ (carry out) the plan.The book is said to have been translated into English 比较: He is said to ___________ (translate) the novel.5、作表语My wish is to be taken to the park.比较: My wish is to ___________ (go) to college.6、作定语The meeting to be held tomorrow is important.7、作状语The letter must be sent quickly in order to be received by the weekend.She is sent abroad to be trained.He hurried to the station, only to be told the train had left.I’m happy to have been invited to the party.小结：确定好不定式与其逻辑主语的关系，是确定用不定式的主动式还是被动式的依据, 而找出不定式的逻辑主语又是关键,那如何确定出不定式的逻辑主语呢?1)不定式作主语时：在it is /was + adj/n.+ for sb./sth + to do/to be done 结构中,for sb./sth就是其逻辑主语；而在有些句式中没有明显的逻辑主语，这时需根据句意挖掘出所隐含的逻辑主语。
高中英语不定式被动式及完成式用法不定式被动式的构成与用法说明不定式被动式的构成不定式主动式的基本形式是to do，不定式被动式的基本形式则是to be done。
如：I was very glad to invite him. 能邀请他我很高兴。
(不定式to invite为主动式)I was very glad to be invited. 我很高兴受到邀请。
(不定式to be invited为被动式)He ordered the soldiers to go by air. 他命令士兵乘飞机去。
(不定式to go为主动式)He ordered the goods to be sent by air. 他命令把货物空运。
(不定式to be sent为被动式)不定式的被动式的用法说明1. 不定式到底用主动形式还是被动形式，往往取决于句子的意思，即意思上为主动就用主动形式，意思上为被动就用被动形式。
如：He asked to be forgiven. 他请求原谅他。
You are to be congratulated. 你应当受到祝贺。
It’s annoying to be interrupted. 让人打扰是很令人不高兴的。
I had to shout to be heard. 我必须叫喊对方才能听得见。
2. 要注意主动表被动的情形。
一般说来，表示主动意义，不定式用主动式；表示被动意义，不定式用被动式。
但是，有个别时候，虽然意义上是被动的，但不定式却要用主动式。
如：I want something to drink. 我想喝点什么。
The poem is not easy to understand. 这首诗不容易理解。
Your writing is impossible to read. 你的书法没法认。
以上各例中的不定式to drink, to understand, to read均为主动形式，但均表示被动意义。
动词不定式有两种被动式, 即一般式和完成式, 例如do 的被动式有to be done, to have beendone 。
只有及物动词和相当于及物动词的短语才有不定式的被动式。
一般说来, 当不定式的逻辑主语是不定式动作的承受者时, 该不定式要用被动式。
例如: He asked to be sent to work in that factory. 他要求派他去那个工厂工作。
These books are not allowed to be taken out ofthe room. 这些书不许带出室外。
但在某些情况下, 不定式虽然表示被动意思,用的却是主动形式。
常见的有下列几种情况:一、在某些固定句型中, 动词不定式作定语,用主动形式表被动意义。
1) have( give, show )sth. to do 在这种句型中的不定式与前边的名词有动宾关系, 又和句中另一名词或代词构成主谓关系。
例如: I have a lot of things to do this afternoon. to do 与things 是动宾关系, 与I 是主谓关系。
否则, 在表示被动意义时, 仍需要被动式。
试比较:Have you anything to do this afternoon? 今天下午你有事要做吗?( to do 是由you 发出的)Have you anything to be taken to your parents? 你有要带给你父母的xx 吗? (谁带不得而知)再如:Please get me something to read. 请给我弄点读的材料。
He'll show you the right path to take. 他会给你指出要走的正确的路。
2) It ( This, That )＋be＋a／an＋adj. ＋n. ＋to do在这种句型中, 不定式与前面的名词有动宾关系。
