英语语法:不定式(3)
注意:在与 why连用时,只用于 why或 why not开头的简短疑问句中,后面紧跟的动词不定式不带 to.例如:
Why not have a rest?
9)不定式在句中用主动式还是被动式。多数情况下是容易判别的,但有时的确比较复杂,请注意以-下几点:
A)不定式修饰的名词或代词和不定式逻辑上构成主谓关系时,不定式往往用主动形式.
Have you got a key to unlock the door?
(A key unlocks the door.)
B)不定式和它前面被修饰的名词或代词构成逻辑上的动宾关系,又和该句主语构成逻辑上的主谓关系时,不定式常用主动形式.
I have got a letter to write.( I write letter.)
He needs a room to live in.( He lives in a room.)
I know what to do.( I do what.)但这句如改为下列形式,不定式就得用被动形式: I know what is to be done.
这是因为 what is to be done是宾语从句,从句中的主语 what是动词 do的动作对象
C)不定式作表语形容词的状语,和句中主语构成逻辑上的动宾关系时,不定式多用主动形式,这是因为人们往往认为形容词后者去了 for one或 for people.例如:
He is hard to talk to.( to talk to him.)
The book is difficult to understand.( to understand the book.)
但如果强调句中的受事者时,亦可用不定式被动式,例如:
The handwriting is very difficult to be read.
The box is too heavy to be lifted.
D)在 there十 be的结构中,当说话人考虑的是必须有人去完成某件事时,不定式用主动形式,如果说话人强调的是事情本身必须完成,则用被动形式.
There is a lot of work to do.( Somebody has to do the work.)
There is a lot of work to be done. ( The work has to be done.)
请注意下面两个句子的含义是不同的:
There is nothing to do.意为无事可做,感到十分乏味.
There is nothing to be done.意为某东西坏了,无法使之恢复正常.
2.不定式的时态
l)不定式的一般形式所表示的动作,通常与谓语的动作(状态)同时(或几乎同时)发生,或是在它之后发生.例如:
I saw him go out.
2)如果谓语表示的动作(情况)发生时,不定式表示的动作正在进行,这时不定式就要用进行式.例如:
I am very glad to be working with you.
3)如果不定式的动作发生在谓语动词之前,就要用完成式.例如:
I’m sorry to have kept you waiting.
3.不定式的语态
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,不定式一般要用被动形式。例如: He asked to be sent to work in the countryside. It is possible for our hopes to be realized.