完成式 表示动作发生在谓语动词的动作之前 to have done to have been done 完成进行式 表示动作发生在谓语动词的动作之前且一直进行着 to have been doing 　　He promised to give me a helping hand.(give在promised之后发生)

　　他答应帮助我。

　　We hoped to have finished the work earlier.(finish这一动作发生在hoped之前)

　　我们本希望早点儿完成这项工作。

　　He pretended to be sleeping when I went in.(sleep在pretended发生的时候，正在进行)

　　我进去时，他假装正在睡觉。

　　The book to be published soon is very interesting.(The book是publish的承受者)

　　即将出版的这本书很有趣。

　　She is known to have been dealing with the problem for many years.(deal这一动作发生在is known之前且一直进行着)

　　大家知道她很多年都在处理这个难题。

　　[即时训练1]　单句语法填空

　　①Don't wait for him.He is said to have gone(go) to Shanghai.

　　②You are supposed to be sleeping(sleep)now.Why are you still in the office?

　　③In order to be chosen(choose)in the first round，the girl made careful preparations for the singing competition.

　　二、动词不定式的句法功能

　　1．不定式作主语

　　直接把动词不定式置于句首的情况不多，多数情况用it作形式主语，把真正的主语--动词不定式置于句末，特别是不定式短语较长时。动词不定式作主语，谓语动词用第三人称单数形式。带疑问词的不定式短语作主语常置于句首。

　　To be here with all of you is a pleasure for me.

　　与你们所有人在这儿，我很高兴。

　　It is important to master a foreign language.

　　掌握一门外语很重要。

How to make requests politely is important.