不定式由“to+动词原形”构成,其否定形式是“not to+动词原形”。不定式可以带宾语或状语构成不定式短语,没有人称和数的变化,但有时态和语态的变化。不定式可作主语、宾语、状语、表语和定语,但不能单独作谓语。
1.不定式的时态及语态
|
时态 |
主动 |
被动 |
意义 |
例句 |
语态 |
|
一般 |
to do |
to be done |
与谓语动词同时发生或以后发生 |
I’m glad to see you. |
当不定式逻辑上的主语是这个不定式所表示的动作的承受者时,不定式须用被动形式。如:He asked to be sent to work in Tibet. This book is said to have been translated into many languages.[ |
|
进行 |
to be doing |
|
表示谓语的动作(情况)发生时,不定式表示的动作正在进行 |
He pretended to be reading a book when I
came in. |
|
|
完成 |
to have done |
to have been done |
先于谓语动作发生 |
We seem to have met each other before. |
|
|
完成进行 |
to have been doing |
|
先于谓语动作发生而又延续到谓语动作发生后 |
He is said to have been studying abroad,but I don’t know which country he
is studying in. |