不定式的时态和语态 

1.一般式to do，所表示的动作一般发生在谓语动词之后，但也可以在谓语动词之前，或几乎同时发生。 

例句：I have a lot of work to do. 

I am glad to see you. 

2.不定式的完成式to have done，表示的所有动作都发生在谓语动词之前。 

例句：I am sorry to have brought you so much trouble. 

She seems to have read the book. 

3.不定式的进行式to be doing，表示的所有动作与谓语动词同时发生。 

例句： 

It happened to be raining when I arrived. 

The child pretended to be sleeping when his mother came in. 

4.不定式的完成进行式to have been doing，表示的所有动作，从谓语动词之前某一个时间开始，进行到谓语动词所表示的时间。 

例句： 

He is said to have been writing a play for months. 

The man seemed to have been lying on the ground for a while. 

5.不定式的被动式to be done，表示的动作是被动的，一般发生在谓语动词之后，但也可以在谓语动词之前，或几乎同时发生。 

例句： 

The new railway is said to be opened to public the next month. 

It is an honor for me to be asked to speak here. 

有时不定式表示的动作虽然有被动意义，但仍使用主动形式，这种现象主要出现于以下几种情况： 

1）在一些形容词如easy, difficult, hard, nice, interesting, important, pleasant, dangerous, heavy, light, fit等之后。 

例句：My bag is very heavy to carry. 

The sentence is not easy to understand. 

2）在 there be 句型中的不定式，如果是被动的含义，可以用主动式，也可以用被动式。 

例句： 

There is nothing to do. 

There is nothing to be done. 

6.不定式的完成被动式 to have been done，表示的动作是被动的，发生在谓语动词之前。 

例句： 

The book is said to have been translated into English. 

He was proud to have been chosen the captain of the team.